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Author Topic: Failed second test of high voltage power supply with tubes?  (Read 2195 times)

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Offline Lowercase

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Failed second test of high voltage power supply with tubes?
« on: April 23, 2023, 04:28:20 PM »
Passed the first stage of the test with flying colors on 10U, 14U and 15U. Proceeded to the second part of the test. Placed the tubes in the correct orientation, larger pins in the back. Then back over and plugged everything in. Did not get a reading on 53U or 65U, noticed a slight electronics/warm smell then subtle smoke around 13 appeared. Unplugged quickly, discharge took about the same time as first go around. Once that was done I removed the tubes, checked for anything amiss and conducted the first part of the test again. Passed again on the same terminals with no issues. Any ideas on what to check next? No signs of any burnt components and no blown fuse. Didn’t want to directly proceed again with tubes without a second opinion.
« Last Edit: April 24, 2023, 07:35:30 AM by Lowercase »

Offline Paul Birkeland

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Re: Failed second test of high voltage power supply with tubes?
« Reply #1 on: April 24, 2023, 04:46:10 AM »
I would post some build photos just in case, but you might have had some debris shorting something out.
Paul "PB" Birkeland

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Offline Lowercase

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Re: Failed second test of high voltage power supply with tubes?
« Reply #2 on: April 24, 2023, 07:12:44 AM »
Didn’t see any rogue leads or debris in the area, but maybe something fell out when i flipped it back over. Images of the overall build and the area in question.
« Last Edit: April 24, 2023, 07:14:15 AM by Lowercase »

Offline Paul Birkeland

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Re: Failed second test of high voltage power supply with tubes?
« Reply #3 on: April 24, 2023, 07:30:22 AM »
Things look pretty tidy in there, I would be inclined to think there was a tiny piece of debris that cooked itself away.
Paul "PB" Birkeland

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Offline Lowercase

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Re: Failed second test of high voltage power supply with tubes?
« Reply #4 on: April 24, 2023, 07:32:29 AM »
Things look pretty tidy in there, I would be inclined to think there was a tiny piece of debris that cooked itself away.

That’s good to hear! I will proceed with the second part of the test and report back.

Offline Lowercase

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Re: Failed second test of high voltage power supply with tubes?
« Reply #5 on: April 24, 2023, 07:45:42 AM »
Same result, but no smoke. Transformer hummed quite a bit too.  :(

Offline Paul Birkeland

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Re: Failed second test of high voltage power supply with tubes?
« Reply #6 on: April 24, 2023, 07:49:00 AM »
How are the voltages?  Are the transformer screws nice and tight?
Paul "PB" Birkeland

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Offline Lowercase

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Re: Failed second test of high voltage power supply with tubes?
« Reply #7 on: April 24, 2023, 07:53:04 AM »
I’m getting 0VDC on terminals 53 and 65. The transformer is tight. I made sure to get it extra secure when assembling after reading others report humming when not tightening it down enough. I also didn’t get any humming when doing the first part of the test. Want me to test voltages on 10, 14 and 15 with tubes in? Afraid I’m going to damage something, but maybe I’m being overly cautious?

I’ve triple checked the wiring on both the B and C sockets and see nothing amiss. Something up with the tubes themselves since the first part of the test is passing?
« Last Edit: April 24, 2023, 11:27:32 AM by Lowercase »

Offline Paul Birkeland

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Re: Failed second test of high voltage power supply with tubes?
« Reply #8 on: April 24, 2023, 11:41:21 AM »
The white wires you have going to the rear terminal strips are not wired properly and will cause these issues. 
Paul "PB" Birkeland

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Offline Lowercase

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Re: Failed second test of high voltage power supply with tubes?
« Reply #9 on: April 24, 2023, 12:24:38 PM »
It’s always good to be humbled from time to time! :) I think I stared at every connection for a good minute or two.

Fixed the error(s) and perfect measurements!

Thank you Paul!