Need help trouble shooting voltages

[Doc B]

If your voltages now measure OK the next place to start looking is in the signal path. Check over the RCA jacks to be sure the right one hasn't had a wire break. This can happen sometimes when an interconnect cable is inserted or removed if the jack is a little on the loose side. If that is all OK move on to the volume pot and make sure there are no cold solder joints or shorted wires.

 

[Incendie]

https://photos.app.goo.gl/KD8iyWniNVbf2Hdt8

I checked and reflowed most of the red wire connections, but still nothing. Tried to take a few photos of the connections. I even checked that there's no resistance along the red wire coming from the right (red) input to the lug on the POT.

 

[Paul Birkeland]

The red wire going to the center pin of the RCA jack is not soldered.  There is solder there, but it's not flowing around the wire.  There could be enough flux in there that the wire is totally insulated.

 

[Incendie]

https://photos.app.goo.gl/DE6sCWSFJeLZC6UF8

Re-did it and still nothing in the right side

 

[Paul Birkeland]

I was looking over your photos and noticed that the 2.49K resistors on the headphone jack are a bit charred. Was there an issue with the initial build that caused this? If you plug in a 1/4" to 1/8" headphone adapter but no headphones, what DC resistance do you get from ground to 6 and ground to 10?

 

[Incendie]

I actually didn't notice that they were discoloured like that and I don't remember there being any issues that may have caused that. I'm away from it right now, but last I checked the resistance was 2.45k because that was what caused the original mixup in the resistance checks earlier in this thread.

 

[Paul Birkeland]

There's another set of tests we can do if your meter has a reasonable number of AC scales.  Can you post the model of your meter?

 

[Incendie]

Mastertech MAS830

 

[Paul Birkeland]

Yeah, the 200V AC range won't resolve what needs to be measured.  The $20 meter at Harbor Freight will do the job, or if you can borrow one with a 2V AC scale, we can send a tone into your amp and measure where it doesn't exit.

 

[Incendie]

It took me a while, but I finally got my hands on a new multimeter, the MTP 2322. Let me know if this would be suitable and what needs to be done next.

Thanks

 

[Paul Birkeland]

That meter will do the job.  Set it to the 2V range on the AC section.  Play a 60Hz tone with your phone into the input of the Crack, then measure the AC voltage between ground and the center pin of each RCA jack.

-PB