Another failed voltage check

SamJ · 164

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Offline SamJ

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on: July 10, 2025, 11:22:06 AM
Same as figby, after a good resistance check and lots of comparing picture to result, I have some wayward DC voltages. Of note the two LEDs for the right channel aren't lighting up.  I reflowed all the connections, including at the terminal strips.  All tubes glow normally and I haven't had any pops or buzzing, smoke, etc.  I'm sure I screwed something obvious up. 

here are my wayward voltages:

14. 1.856 (170-230)
15. 0.302 (58)
17.  1.007 (0)
19.  2.996 (395)
20.  2.848 (365)
34.  3.014 (392)
36.  .305 (58)
37.  .302 (58)
39.  .302 (58)
40. .299  (58)

Sam



Offline Paul Birkeland

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Reply #1 on: Yesterday at 05:01:09 AM
Do any of the 130 ohm 2W resistors measure open when you check them with your meter (with the amp off)?  If so, you likely plugged in a 2A3 without paying attention to the fat vs. skinny pins, which will destroy one of those resistors and leave you with dead voltages on one side (or both if you are unlucky and force both 2A3 tubes into the sockets the wrong way). 

As always, it's also a good idea to post build photos along with stuff like this. 

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline SamJ

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Reply #2 on: Yesterday at 05:10:14 AM
PB,

I'll check that and get some photos up as well.  I don't THINK i had the 2A3s installed incorrectly, but there's alway a chance there. 

Thanks for the quick response!

Sam



Offline SamJ

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Reply #3 on: Yesterday at 05:31:50 AM
The 130 ohm 2w resistor between 31 and 34 is reading either open or sometimes something really low like 1.9 (tough to get the leads in there), so looks to be bad.



Offline Paul Birkeland

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Reply #4 on: Today at 03:03:16 PM
I don't see anything obvious.  I'd snag some replacement 130 ohm 2W resistors from us or online, then attempt to fire up the amp again once that open resistor is replaced.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man