Measuring from the emitter leg (on the leg itself) from one output transistor to the other in each channel, what is the resistance?
Do this for both channels. The meter probes must be on the legs of the transistors, not on any point on the board.
Do this for both channels. The meter probes must be on the legs of the transistors, not on any point on the board.
Now this feels like progress! One side seems fine showing around 0.08-0.10 ohms. The other channel shows nothing at all. I confirmed the leads were touching properly but no resistance at all. Multimeter blips for a second sometimes and then returns back to what it reads when the leads aren't touching anything.
I saw something when you posted the last image of the transistor near the diode that was concerning. The problem is described below.
https://www.diyaudio.com/community/threads/sounstream-lw4-620-dc-on-output.428387/post-8027214
You will need to strip away all of the fixative on the emitter resistors so that the connections on the top of the board are visible. Using a heat gun to heat the bottom of the board allows many of the soft fixatives to pull free more easily.
https://www.diyaudio.com/community/threads/sounstream-lw4-620-dc-on-output.428387/post-8027214
You will need to strip away all of the fixative on the emitter resistors so that the connections on the top of the board are visible. Using a heat gun to heat the bottom of the board allows many of the soft fixatives to pull free more easily.
By fixative i assume that is the black glue like substance on the board? I should heat this up and remove it?
Yes, the black stuff. If it's a soft/flexible material, heating the board from the bottom will sometimes help it come off more easily.
I tried heating the board and prying the black goo off, but it doesn't seem to want to leave. I am worried about heating the board too much too. It seems to be underneath some components and I don't think it'll go without removing them (mainly the ceramic resistors). Is it necessary to remove the black glue completely? I also noticed this when trying to clean it up. This is on the channel that there is no resistance between both output transistors. It looks to be some sort of corrosion or substance on top of the solder joint above R169.
I do not. They look like they are planted against the board. As they are square on the bottom it looks like they are pressed against the bottom of the board. There is not much room between it and the PCB from what I can see.
