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Pete Millett High Voltage Power Supply- Need help
Pete Millett High Voltage Power Supply- Need help
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Old 8th April 2021, 02:39 AM   #11
PRR is offline PRR  United States
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Pete Millett High Voltage Power Supply- Need help
Quote:
Originally Posted by spliteye View Post
... I didn't use 807s. ...6L6 ...I used 6N3C tubes ....
It goes without saying that I did use the correct pins....
I'm inexperienced as a builder...
Hm.
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Old 8th April 2021, 07:06 AM   #12
jan.didden is offline jan.didden  Europe
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Ketje, you suggest to connect the V7 load resistor (330k) to the output B+. Would that still work if the B+ is set to say 25V??

My suggestion is to connect the 330k to RAW_B+. I still am convinced that this single change will fix all the problems, which really is only ONE problem: anode voltage for V7.
Assuming of course no other mistakes were made...

Jan
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Old 8th April 2021, 10:04 AM   #13
Ketje is offline Ketje  Belgium
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As I wrote before, connecting the 330k to a positive voltage is no good idea.The zeners in the current limit get biased in the wrong way.
There is no need for a positive voltage.
Only the values of R12 and R27 are odd, not the values to get 0...400V out with the 100k potmeter.
Here the voltages I expect in respect to the cathode of the control tube.
Mona
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Old 8th April 2021, 10:21 AM   #14
jan.didden is offline jan.didden  Europe
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Yes but how does that look when B+ is dialed down to 0V?

Jan
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Old 8th April 2021, 01:01 PM   #15
Ketje is offline Ketje  Belgium
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Quote:
Originally Posted by jan.didden View Post
Yes but how does that look when B+ is dialed down to 0V?
With the 36V zener for the max current limit there is a problem, there isn't enough negative voltage to block the pass tube(s).
With the 15V limiter all is well if there is enough load.
If there isn't the circuit fails and the output remains to high.
Problems of a circuit with an active pull-up and a passive pull-down.
Mona
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Old 8th April 2021, 08:50 PM   #16
spliteye is offline spliteye
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Just a quick response until I can continue investigating the circuit with your suggestions.



Quote:
Originally Posted by jan.didden View Post
Ketje, I don't think he reads what we post ...

Jan

Jan, I already connected the 330k to RAW B+. This did not work. I have been reading what you post, I think there was a misunderstanding.

Quote:
Originally Posted by Ketje View Post
He checked the Vg2 so I think he does.
Looks like the pass tubes are doing nothing, if it's not Vg2 then are heaters on ?
Or a allmost short circuit at the output, D17 (1N4007) in the right direction ?
Mona
Hello Mona, I will check D17 and make sure I didn't put it in backwards. It's absolutely possible. Likely won't be able to check until Saturday, but I will get back to you by then.


Quote:
Originally Posted by PRR View Post
Hm.
Pins 2 and 7 are connected as heaters. Pin 8 is cathode and has the 10 ohm resistor tied to pin 2, filament. Pin 5, control grid, 1k resistor to pin 7 error amp. Pin 4 to 150 ohm resistor to screen supply. Is this incorrect? This is how I read the schematic. The "goes without saying" wasn't intended to be arrogant, I just made sure to not wire it like an 807.

Daniel
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Old 8th April 2021, 09:12 PM   #17
jan.didden is offline jan.didden  Europe
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OK thanks for letting me know. Maybe Ketje has the better idea.

Jan
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