Please tell me a few things.. You said you never managed to get into adjustment menu and then later you show a picture of the switch test ? So you got the switches to work to get to the menu I suppose?

You give your voltages but did you check them again once you had replaced Q2 a second time ? Because your 12v was very low and abnormal , and the circuitry that checks the rows / columns (for your switches) relies on that 12v. If that 12v is not at 12v and stable , you can't expect the circuitry to work properly.

I also see that computer power supply.. What is it connected to ? Was it there for some LED strip add on ? Or is it connected to the power board somehow ?

Before looking any further , I would get that PC power supply out of the equation. Verify all the AC voltages from the transformer , and fix the power board the way it's supposed to be.

3.png

f0f4f171d58b2a51b4148965893bdebaadbf921b.jpg