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Author Topic: Voltage Issues in Reduction Build  (Read 403 times)

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Offline jgeoffreyharris

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Voltage Issues in Reduction Build
« on: February 25, 2018, 06:27:23 PM »
Hi Everyone,

I could use some help - I just finished my Reduction build (stock), and I'm having some voltage issues. So, when I first fired it up, I had very high readings from the A channel, and traced the problem to my connection for the 5w 22ohm resistors for that channel. I re-soldered that tricky connection- voltages back down, I think everything is fine.

Except then the B channel started acting up. Similar issues to A. Very hot LED at the B3 position, faint and flickery LED at B8/9. It flickers whenever I poke around connection 18 and 26 especially. No tube glow on that channel. I'll list my voltages that are currently out of line:

18: 152.8
19: 141
20: 125
37: 2.3

Others that are just slightly out:
44: 173.5
52, 53: 172.5
56, 57: 142.8
59: 156.7
60: 157.5
I know these may be within the percentage margin- just mentioning in case it's helpful.

I re-flowed solder on any points that looked iffy. I've checked and re-checked my work, things appear good. What do you all think? I've built a Crack unit, but I'm still not informed enough to track this down. Thanks so much for your help!

Offline Paul Birkeland

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Re: Voltage Issues in Reduction Build
« Reply #1 on: February 26, 2018, 06:25:39 AM »
No tube glow is the first thing to go after.

There are two runs of shielded twisted pair that feed the center two 5 lug strips to pins 4 and 5 on each 6922.

What voltage do you get at 33 and 37? 

Check over all these connections, if something is amiss here it will cause all sorts of problems with your high voltage readings.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man