Sorry mate, I don't understand what you mean by 1.23v? We are measuring resistance or continuity from the junction of R20 and 37 and C15. There is no voltage to measure.
I just got confused, my bad, can you show me or explain how I am supposed to measure it using my multi meter or otherwise?. I ordered the resistors, but I won't lie I am considering just giving up on this. I must've done something really bad to this. I just don't know how much longer I should go on before it's like "yeah I replaced everything in this"
Hey, no worries, don't let it go now, there is light at the end of the tunnel. With your meter in resistance mode or continuity measure from the junction of R20 and 37 to the positive post of C15. It's the short trace only about 1 cm. We want to confirm there is still a connection there.
If you think the resistors are okay, they didn't look burned as the tracks on the PCB, you can put them back in to at least test it again. It may just have been a dry solder joint that caused the chaos on the pads.
If you go ahead first check then voltage at R37, it it back up to similar to what you are getting on the negative side you can then go back to check the voltage at the opamp pins 4 and 8.
If you think the resistors are okay, they didn't look burned as the tracks on the PCB, you can put them back in to at least test it again. It may just have been a dry solder joint that caused the chaos on the pads.
If you go ahead first check then voltage at R37, it it back up to similar to what you are getting on the negative side you can then go back to check the voltage at the opamp pins 4 and 8.
I think you should unsolder everything from that PCB, check the correctness of each part separately, get a new PCB and start from the beginning. There was thermal overload in many places and that PCB is no longer reliable. Maybe there was carbonization of the PCB locally that now conduct current past the electronic parts.
That's certainly not necessary, at this stage anyway.
1nfinity, have close visual inspection of both sides of the PCB. Can you identify any other burned areas? If so we can have look at those but so far all we have seen is this area around R20 and 37 and there is nothing there stopping this project from working.
They brought me a couple of similar things, DIY burned devices, burned PCBs and parts. The fastest and safest fix is always a new PCB (if feasible). If not, then I patch it because I have no other choice. I remove all the parts fast with a vacuum desoldering gun, measure everything, discard the defective parts, and when I reassemble with the correct components it works immediately, no time wasted. And it looks the best and is reliable in the long run.
R21 and R38 kinda look a little burned, I sent previous pictures, sorry hard to see.
I want to at least try and see where I can get with this in hopes that things work. I am also learning a lot of things to check because I am doing this
Absolutely 1nfinity, I reckon the fix is just around the corner and as you say, doing is learning. You built this to start with and you will get it working again.
Check all around the board where you have already replaced burned resistors near the mosfets for damaged tracks on the PCB. Once all is checked and the parts are back in you can go through the voltage test points you have measured before to see if they are where they should be.
Check all around the board where you have already replaced burned resistors near the mosfets for damaged tracks on the PCB. Once all is checked and the parts are back in you can go through the voltage test points you have measured before to see if they are where they should be.
Can I suggest you clean this board with a PCB cleaner, then investigate further ? It's difficult to see the track to pad connection. I've had the great pleasure of repairing several Musical Fidelity amplifiers which have been slowly cooking themselves over the years and now I use a scalpel to gently scrape away burnt board then clean it with a brush and Fluxclene from Electrolube. It's not a nice chemical but it does clean everything from a board very easily and leaves it sparkling and it's very easy to then see the condition of tracks and pads. You might just about get continuity with a meter but when the amp is running the joint doesn't work.
I'd also suggest doing what Zum911 said, join the leads but also use a cut off lead to join to the capacitor too, in case the track is poor.