M800 - No Volume

[DrumBuster]

Hello everyone, after neglecting my project for almost a year, I finally built my M800, when trying it out, I noticed I had no volume. Bypass works great, j201s all biased to the right voltage (4.5v ish) save for one of them not doing it. It stays stuck at 2.7, is it possible that is the culprit? I got a 2N5458 just in case is a faulty transistor. I check every solder and ground and everything seems fine, led lights up. What it can be the issue? Thanks

 

[DrumBuster]

Okay, I tested all 6 transistors and their trim pots, all work but I noticed the tone trimpot (I know that transistor has a fixed bias so that trimpot doesn’t do anything besides eq), I don’t see anything on the meter

 

[music6000]

Okay, I tested all 6 transistors and their trim pots, all work but I noticed the tone trimpot (I know that transistor has a fixed bias so that trimpot doesn’t do anything besides eq), I don’t see anything on the meter

Are you getting around 9v+ from the Drain on Q4, If not we will have to do a Continuity test on that!

 

[music6000]

Continuity Test all these Colour matched Circles as requested & report:

 

[DrumBuster]

Continuity Test all these Colour matched Circles as requested & report:View attachment 8671

Thanks! Will try again

 

[DrumBuster]

Every color combination provided gave me good results when doing the continuity test

 

[DrumBuster]

I installed (horribly) the new transistors and they’re not biased at 5v ish each except the fixed one. But I noticed some capacitors at the bottom of the circuit arent responding to the test

 

[music6000]

Every color combination provided gave me good results when doing the continuity test

Continuity Test all these Colour matched Circles and report:

 

[music6000]

I installed (horribly) the new transistors and they’re not biased at 5v ish each except the fixed one. But I noticed some capacitors at the bottom of the circuit arent responding to the test

Are you getting around 9v+ from the Drain on Q4 (Fixed One).
Continuity only tests if the trace has been damaged between Solder pads, Not across components.

 

[DrumBuster]

Are you getting around 9v+ from the Drain on Q4 (Fixed One).
Continuity only tests if the trace has been damaged between Solder pads, Not across components.

Typo, they’re biased! Sorry

 

[DrumBuster]

Continuity Test all these Colour matched Circles and report:
View attachment 8678

No issues!

 

[DrumBuster]

I'm checking the transistors' drain voltage, just to be sure again. Noticed something, Q5's trimmer doesn't work at all, is still stuck at 8.9+v at drain.