Collins 516f 2 Power Supply for Sale
Hi there, first post for me here in this group. I could not see where to search for similar posts, will look into that further.
I have updated the capacitors and resistors in my 516F-2 using a great PCB from Paul at Electronic specialties.
Went in well, nice kit, easy to follow. I have a dual primary 'late model' unit with serial 20448
First power up the 5U4GB arced over, so I just replaced spare as It seemed to be a bad NOS tube.
Now stable I started to measure and have found 1200vdc on the HV and 294 on LV. By that point I turned it off immediately and have not tested the filament winding.
This board can be used for either solid state or tubes, so given that I have not used the plug-in solid state rectifiers this seems very high voltage!
So given that there are not a huge number of components and I have replaced over half of them already, where do I look now please, and is this possibly a choke issue?
If the choke is not resonating at all would this cause such high voltage unloaded? I was expecting around 920vdc HV and 250ish LV. The bias is there and not far off the correct values.
Any ideas?
Thanks for looking, 73
Stew ZL2VA
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.
Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.
I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Hello Steve, Here is the normal load curve for the 516F-2 plate supply
The problem is likely to be R4 or R5 open circuit. Those are the 25K 25W brown Ohmite(if originals present) located in the ventilated aluminium enclosure on the rear upper chassis.
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
toggle quoted messageShow quoted text
On Fri, Sep 4, 2020 at 9:43 AM <nz.zl2va@...> wrote:
Hi there, first post for me here in this group. I could not see where to search for similar posts, will look into that further.I have updated the capacitors and resistors in my 516F-2 using a great PCB from Paul at Electronic specialties.
Went in well, nice kit, easy to follow. I have a dual primary 'late model' unit with serial 20448
First power up the 5U4GB arced over, so I just replaced spare as It seemed to be a bad NOS tube.
Now stable I started to measure and have found 1200vdc on the HV and 294 on LV. By that point I turned it off immediately and have not tested the filament winding.
This board can be used for either solid state or tubes, so given that I have not used the plug-in solid state rectifiers this seems very high voltage!So given that there are not a huge number of components and I have replaced over half of them already, where do I look now please, and is this possibly a choke issue?
If the choke is not resonating at all would this cause such high voltage unloaded? I was expecting around 920vdc HV and 250ish LV. The bias is there and not far off the correct values.Any ideas?
Thanks for looking, 73
Stew ZL2VA
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
toggle quoted messageShow quoted text
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Stew,
Re the high voltage, this can be caused by the difference between
the line frequency, in the US it is 60Hz, whereas I think it is 50Hz in Zl.
Changing the value of C1 can help in reducing the voltage, I have do this and it reduced the voltage by 200/300 volts.
I increase the value of C1 to .22uf,as far as I can remember.
Try it.
Hope this is of some help.
73's
Jim
Ei2BB
toggle quoted messageShow quoted text
On Fri, 4 Sep 2020 at 08:43, <nz.zl2va@...> wrote:
Hi there, first post for me here in this group. I could not see where to search for similar posts, will look into that further.I have updated the capacitors and resistors in my 516F-2 using a great PCB from Paul at Electronic specialties.
Went in well, nice kit, easy to follow. I have a dual primary 'late model' unit with serial 20448
First power up the 5U4GB arced over, so I just replaced spare as It seemed to be a bad NOS tube.
Now stable I started to measure and have found 1200vdc on the HV and 294 on LV. By that point I turned it off immediately and have not tested the filament winding.
This board can be used for either solid state or tubes, so given that I have not used the plug-in solid state rectifiers this seems very high voltage!So given that there are not a huge number of components and I have replaced over half of them already, where do I look now please, and is this possibly a choke issue?
If the choke is not resonating at all would this cause such high voltage unloaded? I was expecting around 920vdc HV and 250ish LV. The bias is there and not far off the correct values.Any ideas?
Thanks for looking, 73
Stew ZL2VA
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
toggle quoted messageShow quoted text
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
toggle quoted messageShow quoted text
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Richard and Jim,
If i continued on the bleeder path logically could i then look into using lower value resistors to produce the ideal unloaded voltage or does this upset the resonance curve?
I'd be really interested in trying to calculate this or would i just have to plot it? I guess its not as simple as placing a load on each output as they all work together.
This above interests me from a line voltage point of view although if the filament voltage is too high then back to reducing mains I go.
Reason i am thinking it is the bleeder is that i had left the original LV 25k resistor in place as this was in test, but replaced the 2x 24k HV resistors with 33k as I had these and didn't have to wait 15days for delivery.
The LV is high at 294v but not proportionally as high as the HV at 1200v.
My logic then says provided my choke is ok i should be able to get both output voltages to be proportionately the same then buck the input voltage to bring the filament to 6.3v.
Thanks
Stew
ZL2VA
toggle quoted messageShow quoted text
On Sat, 5 Sep 2020, 7:34 AM richard.dismore, <erigid@...> wrote:
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Hello Richard,
Yes years ago, I had a problem with a 516F-2.At the time there was
a discussion about what C1 did.
Apparently it is a resonont circuit with L1.
To cut a long story short, I did some calculations.
The difference was the fact that 60 HZ and 50 HZ came out with different resonant points.
Doing calculations I came up with around .22uf for 50Hz.
In my case it made the voltage drop by 250/300 volts.
A lot depends on the actual inductance of L1.
Worth a try and play around with values of C1.
Old brain is not what it was but sure worth a try, if you are stuck I have some HV caps I can send you.
Take care and stay safe.
73's
Jim
Ei2BB
toggle quoted messageShow quoted text
On Fri, 4 Sep 2020 at 20:34, richard.dismore <erigid@...> wrote:
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Hi Stew, You are on the right track. 6146's are quite happy with 1kV on the anode, the problem is the creepage (ie leakage) to earth in the circuit from the cathode of the 5R4 in the 516F-2. Replacing the valve base with ceramic eliminates a weak point as the phenolic bases are prone to tracking, and the dress of the multicore cable attachment is significant because if the earth braid deatches the cable can rotate and reduce the clearance to the plate connection. It looks like your LV is an open circuit value. Measure it under load connected to a KWM2A while tuning or on RX with full audio output.I don't think it is signifying a problem. Replace your 33K's on the plate supply with 25K's as soon as you are able. BTW the load curve was plotted using different series/parallel combinations of 40,60, and 100W incandescent light bulbs.
73 and have fun
Richard
F4WCD (ZS6TF)
Past President AWA of SA
toggle quoted messageShow quoted text
On Fri, Sep 4, 2020 at 9:47 PM Stewart Thorp <nz.zl2va@...> wrote:
Richard and Jim,
If i continued on the bleeder path logically could i then look into using lower value resistors to produce the ideal unloaded voltage or does this upset the resonance curve?
I'd be really interested in trying to calculate this or would i just have to plot it? I guess its not as simple as placing a load on each output as they all work together.
This above interests me from a line voltage point of view although if the filament voltage is too high then back to reducing mains I go.
Reason i am thinking it is the bleeder is that i had left the original LV 25k resistor in place as this was in test, but replaced the 2x 24k HV resistors with 33k as I had these and didn't have to wait 15days for delivery.
The LV is high at 294v but not proportionally as high as the HV at 1200v.
My logic then says provided my choke is ok i should be able to get both output voltages to be proportionately the same then buck the input voltage to bring the filament to 6.3v.
Thanks
Stew
ZL2VA
On Sat, 5 Sep 2020, 7:34 AM richard.dismore, <erigid@...> wrote:
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Jim and Richard this is absolutely great info. Great to see example too Richard of load bank and Jim the capacitor values affecting resonance is an excellent point.
Some say these older circuits are super simple but try calculating everything correctly if there were no examples to follow. I work in tech and am an industrial sparky and i have great respect for the innovations at the time in this era of radio.
These Collins units actually to me mean a lot more than my IC-7300 that has great sound and all but i can't open it up and try to nut out it's operation let alone fix it.
I am a new ham and new to tubes but understand some principles and am learning heaps.
This power supply is the first move in a big project resurrecting a really nice Collins shack that has not been on air for 20yrs. My aim is to get them all able to be used reliably and for some time to come. The Collins quality I witness every time i peer into one of these units should make this possible.
I also have a 618S-1 from a DC-8 which i probably will not be able to use due to missing the 180L-1 tuner and Control head but i am thinking about mounting that on the wall minus covers as it is just a lovely bit of engineering and has a great story.
Cheers all and 73
Stew
ZL2VA
toggle quoted messageShow quoted text
On Sat, 5 Sep 2020, 8:37 AM richard.dismore, <erigid@...> wrote:
Hi Stew, You are on the right track. 6146's are quite happy with 1kV on the anode, the problem is the creepage (ie leakage) to earth in the circuit from the cathode of the 5R4 in the 516F-2. Replacing the valve base with ceramic eliminates a weak point as the phenolic bases are prone to tracking, and the dress of the multicore cable attachment is significant because if the earth braid deatches the cable can rotate and reduce the clearance to the plate connection. It looks like your LV is an open circuit value. Measure it under load connected to a KWM2A while tuning or on RX with full audio output.I don't think it is signifying a problem. Replace your 33K's on the plate supply with 25K's as soon as you are able. BTW the load curve was plotted using different series/parallel combinations of 40,60, and 100W incandescent light bulbs.
73 and have fun
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 9:47 PM Stewart Thorp <nz.zl2va@...> wrote:
Richard and Jim,
If i continued on the bleeder path logically could i then look into using lower value resistors to produce the ideal unloaded voltage or does this upset the resonance curve?
I'd be really interested in trying to calculate this or would i just have to plot it? I guess its not as simple as placing a load on each output as they all work together.
This above interests me from a line voltage point of view although if the filament voltage is too high then back to reducing mains I go.
Reason i am thinking it is the bleeder is that i had left the original LV 25k resistor in place as this was in test, but replaced the 2x 24k HV resistors with 33k as I had these and didn't have to wait 15days for delivery.
The LV is high at 294v but not proportionally as high as the HV at 1200v.
My logic then says provided my choke is ok i should be able to get both output voltages to be proportionately the same then buck the input voltage to bring the filament to 6.3v.
Thanks
Stew
ZL2VA
On Sat, 5 Sep 2020, 7:34 AM richard.dismore, <erigid@...> wrote:
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
I am not in to show and tell really but attached a pic of proposed setup.
The units are all sitting there unplugged at mo. I have a deal hopefully 'locally' where I am swapping another 32S-3 for a 75S-3 to replace the 51S-1 in this photo so the top line can transieve. Also have a 312B-4 to fit in place of the 399C-1. So the idea is that each line horizontally works independently.
Am very fortunate to have a 180S-1 tuner so that will be incorporated somehow.
The 30L-1s are 230vac but I only have a single 516F-2 so am on the hunt for another. There is one for sale in NZ but it is only being sold with 32S-1 which i do not require and is fairly spendy.
I have solid state kits (harbach?) coming for the 30L-1s.
So this is probably going to take a while....!
Absolutely lovely gear. There are a few in NZ and Australia with Collins setups so looking forward to some Collins to Collins QSOs.
Cheers!
Stew
ZL2VA
toggle quoted messageShow quoted text
Jim and Richard this is absolutely great info. Great to see example too Richard of load bank and Jim the capacitor values affecting resonance is an excellent point.
Some say these older circuits are super simple but try calculating everything correctly if there were no examples to follow. I work in tech and am an industrial sparky and i have great respect for the innovations at the time in this era of radio.
These Collins units actually to me mean a lot more than my IC-7300 that has great sound and all but i can't open it up and try to nut out it's operation let alone fix it.
I am a new ham and new to tubes but understand some principles and am learning heaps.
This power supply is the first move in a big project resurrecting a really nice Collins shack that has not been on air for 20yrs. My aim is to get them all able to be used reliably and for some time to come. The Collins quality I witness every time i peer into one of these units should make this possible.
I also have a 618S-1 from a DC-8 which i probably will not be able to use due to missing the 180L-1 tuner and Control head but i am thinking about mounting that on the wall minus covers as it is just a lovely bit of engineering and has a great story.
Cheers all and 73
Stew
ZL2VA
On Sat, 5 Sep 2020, 8:37 AM richard.dismore, <erigid@...> wrote:
Hi Stew, You are on the right track. 6146's are quite happy with 1kV on the anode, the problem is the creepage (ie leakage) to earth in the circuit from the cathode of the 5R4 in the 516F-2. Replacing the valve base with ceramic eliminates a weak point as the phenolic bases are prone to tracking, and the dress of the multicore cable attachment is significant because if the earth braid deatches the cable can rotate and reduce the clearance to the plate connection. It looks like your LV is an open circuit value. Measure it under load connected to a KWM2A while tuning or on RX with full audio output.I don't think it is signifying a problem. Replace your 33K's on the plate supply with 25K's as soon as you are able. BTW the load curve was plotted using different series/parallel combinations of 40,60, and 100W incandescent light bulbs.
73 and have fun
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 9:47 PM Stewart Thorp <nz.zl2va@...> wrote:
Richard and Jim,
If i continued on the bleeder path logically could i then look into using lower value resistors to produce the ideal unloaded voltage or does this upset the resonance curve?
I'd be really interested in trying to calculate this or would i just have to plot it? I guess its not as simple as placing a load on each output as they all work together.
This above interests me from a line voltage point of view although if the filament voltage is too high then back to reducing mains I go.
Reason i am thinking it is the bleeder is that i had left the original LV 25k resistor in place as this was in test, but replaced the 2x 24k HV resistors with 33k as I had these and didn't have to wait 15days for delivery.
The LV is high at 294v but not proportionally as high as the HV at 1200v.
My logic then says provided my choke is ok i should be able to get both output voltages to be proportionately the same then buck the input voltage to bring the filament to 6.3v.
Thanks
Stew
ZL2VA
On Sat, 5 Sep 2020, 7:34 AM richard.dismore, <erigid@...> wrote:
Dear Stew and Jim, Yes it is important to have the correct bleed current because it puts the swinging chokes on the operating point and as you can see from the curve I posted the regulation is rather good for a 60+ year old design. I have not had the same success with the resonant feature. I added the right capacitance to pull it down for 50Hz operation and it made no difference. I disconnected the capacitor and maybe 5 volts down but not conclusive. Jim if you have done some experimentation with measurements I would be very interested to hear of them.
best regards
73
Richard
F4WCD (ZS6TF)
Past President AWA of SA
On Fri, Sep 4, 2020 at 8:41 PM Stewart Thorp <nz.zl2va@...> wrote:
Hi Richard, no problem on the name!
Thanks for the info I may have identified a potential issue as I had replaced the 2 HV bleeder resistors that were OC with 33k. There may be too low bleeder current?
So I'll start there and also try to find a tester for the inductance also.
Autotransformers sure are handy.
Thanks and 73
Stew
ZL2VA
On Fri, 4 Sep 2020, 10:08 PM richard.dismore, <erigid@...> wrote:
Hi Stew,
Sorry to get your name wrong. The absolute values of the mains input or the Plate voltage are less significant than the heater voltage measured at the valveholders on the chassis of the KWM-2/2A or 32S-1/3 which should be 6.3 volts in the interest of valve longevity. I would use a variac to determine what input voltage gives you this and then apply the bucking transformer to achieve this value.
Using the bucking method, much higher loads can be run at reduced voltage with cheap and not so heavy iron, taking care to connect the secondary in the correct sense.A flick test with a battery on the primary using an analogue multimeter on the secondary will give the sense of the windings so that they can be connected to subtract.
The "Auto" connection is preferred as losses are lower=less heat and the current available is slightly higher. As long as the bucking transformer secondary can handle the load current you have an electrical "lever" at your disposal. Also either way your earth leakage still protects you!
On Fri, Sep 4, 2020 at 9:55 AM <nz.zl2va@...> wrote:
Apologies as soon as I posted I found the search function and also some great info about the 516F-2!
So it seems that here being nearly 240VAC I have just got hot in hot out.Can someone please explain to me how the bucking transformer is connected? Is only one winding connected or both in series?
And also what is the benefit of running the dual primary at 110vac? I do have a step down transformer here plenty big enough that would possibly be nicely inefficient and drop the voltage even further.
It seems like this is the way forward, tell please if there is any risk of oscillation or noise with this method, harmonics etc.I saw a post above also for Collins gear lot for sale, I also have some gear here in New Zealand but I guess shipping becomes prohibitive.
Would be very interested in even exchange KWM-2 or a few other options for another 516F-2 - I only have one and am trying to get an S-Line going and another unit that requires a 516F-2.
Thanks
Stew ZL2VA
Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?
Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.
I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Can you forward to me pictures of these components?
David Knepper, W3ST/W3CRA
Secretary, Collins Radio Association
www/collinsradio.us
toggle quoted messageShow quoted text
On 09/06/2020 3:10 AM Stewart Thorp <nz.zl2va@gmail.com> wrote:Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
toggle quoted messageShow quoted text
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Thanks James,
I'll give that a try, hopefully i have the new bleeder resistors in a couple of days just in case that is a major issue.
Cheers
Stew
ZL2VA
toggle quoted messageShow quoted text
On Mon, 7 Sep 2020, 6:52 PM James R. Bartlett, <james.r.bart@...> wrote:
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
LarryW 2E0WDL / K0SDG
Gentlemen, I will risk letting my ignorance show by asking the following question:
My (USA purchased) 516F-2's data plate says "115 VAC 50/60 CPS" (see photo). The question is, wouldn't this imply it was already designed to compensate for the possible differences in line frequency?
Thanks for indulging my novice inquiry!
73,
Larry D. Wilkes
2E Ø WDL / K Ø SDG
+44 (0)7951 345208
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
toggle quoted messageShow quoted text
On Monday, 7 September 2020 08:04, Stewart Thorp <nz.zl2va@...> wrote:
Thanks James,
I'll give that a try, hopefully i have the new bleeder resistors in a couple of days just in case that is a major issue.
Cheers
Stew
ZL2VA
On Mon, 7 Sep 2020, 6:52 PM James R. Bartlett, <james.r.bart@...> wrote:
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?
Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.
I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Hello Larry,
it only lets you know that the transformer can handle 50Hz without overheating. A transformer designed for 60Hz needs an iron core cross section about 17% larger to be able to handle 50Hz.
As far as I remember my 516F-2 manual has the advice to remove the capacitor when using it with 50Hz.
vy 73 Heinz DH2FA, KM5VT
Von meinem iPhone gesendet
toggle quoted messageShow quoted text
Gentlemen, I will risk letting my ignorance show by asking the following question:
My (USA purchased) 516F-2's data plate says "115 VAC 50/60 CPS" (see photo). The question is, wouldn't this imply it was already designed to compensate for the possible differences in line frequency?
<Pasted-image-Mon Sep 07 2020 090330 GMT+0100 (BST).png>
Thanks for indulging my novice inquiry!
73,
Larry D. Wilkes
2E Ø WDL / K Ø SDG
+44 (0)7951 345208
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, 7 September 2020 08:04, Stewart Thorp <nz.zl2va@...> wrote:
Thanks James,
I'll give that a try, hopefully i have the new bleeder resistors in a couple of days just in case that is a major issue.
Cheers
Stew
ZL2VA
On Mon, 7 Sep 2020, 6:52 PM James R. Bartlett, <james.r.bart@...> wrote:
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?
Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.
I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Simple answer Larry is NO.
If you want to use it on 5oHz, put about .22uf in parallel with C1.
Try and get a 1500/1660 volt one.
73''s Jim.
Been there done that. It works.
toggle quoted messageShow quoted text
Gentlemen, I will risk letting my ignorance show by asking the following question:
My (USA purchased) 516F-2's data plate says "115 VAC 50/60 CPS" (see photo). The question is, wouldn't this imply it was already designed to compensate for the possible differences in line frequency?
Thanks for indulging my novice inquiry!
73,
Larry D. Wilkes
2E Ø WDL / K Ø SDG
+44 (0)7951 345208
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, 7 September 2020 08:04, Stewart Thorp <nz.zl2va@...> wrote:
Thanks James,
I'll give that a try, hopefully i have the new bleeder resistors in a couple of days just in case that is a major issue.
Cheers
Stew
ZL2VA
On Mon, 7 Sep 2020, 6:52 PM James R. Bartlett, <james.r.bart@...> wrote:
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?
Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.
I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Hi Larry,
From what i can tell C1 is removed with 400hz aviation power supply, but left in with 50hz supply.
The design it seems used inductance and capacitance values to resonate unloaded circuit at 120hz, the 2nd harmonic of 60hz. In theory it should be adjusted slightly for resonance at 100hz, the 2nd harmonic of 50hz?
But this is looking more and more like a red herring as the main issue while using tube rectifiers anyway from what i can tell is that the design also was orginally for 220vac (or 110vac in your case) but the mains voltage now for us is 240vac or 236/238.
So primarily (see what i did there?) The steps i think i need to take are:
1) replace bleeder capacitors maybe with correct value allowing enough bleeder current to flow in 3 or 4 days when they arrive.
2)reduce filament secondary output to approx 7vac then adjust while connected to heaters with bucking autotransformer or the like
3)check values of chokes and replace if necessary
Take it from there re resonance if needed.
Cunning design. Simple yet kindof not.
Cheers and 73
Stew
toggle quoted messageShow quoted text
Hello Larry,
it only lets you know that the transformer can handle 50Hz without overheating. A transformer designed for 60Hz needs an iron core cross section about 17% larger to be able to handle 50Hz.
As far as I remember my 516F-2 manual has the advice to remove the capacitor when using it with 50Hz.
vy 73 Heinz DH2FA, KM5VT
Von meinem iPhone gesendet
Gentlemen, I will risk letting my ignorance show by asking the following question:
My (USA purchased) 516F-2's data plate says "115 VAC 50/60 CPS" (see photo). The question is, wouldn't this imply it was already designed to compensate for the possible differences in line frequency?
<Pasted-image-Mon Sep 07 2020 090330 GMT+0100 (BST).png>
Thanks for indulging my novice inquiry!
73,
Larry D. Wilkes
2E Ø WDL / K Ø SDG
+44 (0)7951 345208
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, 7 September 2020 08:04, Stewart Thorp <nz.zl2va@...> wrote:
Thanks James,
I'll give that a try, hopefully i have the new bleeder resistors in a couple of days just in case that is a major issue.
Cheers
Stew
ZL2VA
On Mon, 7 Sep 2020, 6:52 PM James R. Bartlett, <james.r.bart@...> wrote:
Stew,
They should befine for expermements.
My calculations worked out around .22uf.
This was taking some self capacitance of the L1 inductor.
Suggest you start aroun d that value.
HV caps suitable are to be found on ebay and , Just Radios in Canada is a very good source.
Good price and excellent delivery.
Hope this is of some use.
73's
Jim
Ei2BB
On Sun, 6 Sep 2020 at 08:10, Stewart Thorp <nz.zl2va@...> wrote:
Quick question regarding getting proper resonance at 50hz line here in New Zealand,
The HV low rating caps seem to be few and far between, so experimentation could be expensive.
I do have a bunch of very early mica HV caps, some are rated at >5000v and test fine now!
Are these OK to use for experimentation?
Also please some help in identifying the green solid state things? Sometimes my tester identifies them as diodes, other times capacitors? And there are no markings
I also have found a document which is attached for measuring resonance, which for my line freq = 100hz. So first stop is putting correct bleeder resistance on HV, then once I've got the filament supply at 6.3v if the HV was still too high I was going to investigate replacing the choke with a few less Henries and a different value at C1
Thoughts?
I have found a 100w 70k resistor that measures at 50k so for now although it is large I will be able to at least check how that affects unloaded voltage and also check chokes etc.
I also looked into a solid state regulator for 800vdc but not looking good - not a lot of applications now require this, and to be honest I really like the simplicity of the resonant choke power supply, not to mention it is in keeping with the radio. I'm sure there are some caveats as well with regards to instantaneous volt drop with a solid state rectifier - I just don't think it is that simple for the HV/HT
Thanks
Stew
ZL2VA
Collins 516f 2 Power Supply for Sale
Source: https://groups.io/g/CCAE-Collins/topic/very_high_voltage_in_516f_2/76625150?p=%2C%2C%2C20%2C0%2C0%2C0%3A%3Arecentpostdate%2Fsticky%2C%2C%2C20%2C2%2C0%2C76625150
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