Voltage Check issue

[Chester]

Hi there,

This is my first kit build and it is exciting (and a little nerve wracking).  I really appreciate the great information on this forum and I have a problem I don't think I've seen.  I have completed the build and the Resistance check is up to spec and the tubes glow.  However the last voltage check (pg. 59) gives some off readings:

Terminals 1 & 11 quickly go up to 600 V and then the multimeter beeps (225-275 is the range given)
Terminals 4 & 14 show 16 V (7-9 range given)
Terminals 6 & 16 show 308 V (110-140 range given)
All other terminals read 0.

I have checked connections.  Is there any place I should start?  I have attached a photo if that helps.  Thanks so much.

Sincerely,
Stephen

 

[Paul Birkeland]

I'd like to know what your wall voltage is and to see your power transformer wiring.  Were the AC voltage checks on the power transformer as expected in the manual?

 

[Chester]

Hi Paul,

Thanks for your response.  M

My wall voltage is 123V
Power Transformer Secondary Test is 9.3 VAC/122 VAC
Raw B+ Voltage is 331 VDC.

I've also attached wiring from both sides of transformer.

Thanks so much.

- Stephen

 

[Paul Birkeland]

In the case where you happened to be in a 220-240V mains country, then your results would be plausible based on a mains wiring error.  Since this isn't possible, then you're 99% looking at a cold solder joint (in the ground path) that is creating the illusion of very high voltages that aren't actually there.  I would reflow all the joints in the amp, bearing in mind that you can probably skip the RCA jacks, power switch, IEC power entry module, and selector switch.  Otherwise, everything else will need to be gone over with your iron and reflowed, and this issue should resolve itself.

https://www.youtube.com/watch?v=EN16Pi7pcfk

 

[Chester]

Paul,

Thank you so much for your speedy reply.  I’ll work on that and let you know.  And, just be clear, do I need to remove the old solder and start again or just reheat the connection until the solder reflows. 

Thanks, again

- Stephen

 

[Paul Birkeland]

You really just want to be sure that the solder you're using has lead in it, and that it's not plumbing nor craft solder.  If you have rosin core leaded solder on there already, then you don't need to remove what's there.

 

[Chester]

Hi Paul,

Well... after doing some continuity checks and reflowing just the transformer connections I retested it.  All checked out!  In retrospect, I think that it may have been a wrong multimeter setting.  My apologies for wasting your time if that was the case.  Lesson learned and THANK YOU! for such a fun build.  I can't wait to try it out.  Here is the picture (first time doing inlay work, as well - so much to learn).

Take care,
Stephen

 

[Paul Birkeland]

That's looking great!

 

[hmbscott]

Thats a Beautiful finish.

 

[2wo]

I like it!