GURU Boot issue when power cycling

[RiP]

I have the same problem with an A500 rev6a too

[RiP]

I've not tested this solution, but most likely it can easily be corrected by putting a small signal diode (e.g. 1N4148) across R711 (A500/A500+) or R611 (A600) with the cathode (stripe side) towards the 5V end of the said resistor, and the anode connected to the side of the resistor that connects to pin 2 of the 555 timer IC.

Thanks, let me try it
Also take a look at the Cyan box, possible to test or should I replace them? :hammer:

[RiP]

I've not tested this solution, but most likely it can easily be corrected by putting a small signal diode (e.g. 1N4148) across R711 (A500/A500+) or R611 (A600) with the cathode (stripe side) towards the 5V end of the said resistor, and the anode connected to the side of the resistor that connects to pin 2 of the 555 timer IC.

Unfortunately it didn't help and I still get random errors at startup (not for the first time) e.g. #00000003.00001970



Also take a look at the Cyan box, should I replace them?

[RiP]

Not sure exactly, I see the dark gray, gray, white then #xxxxxxxx.00C01570 error and sometimes only black screen.
I measured pin3 and seems it's fine.

[RiP]

It only happens when I turn off/on power supply.
Ok, I'll replace C712 too.

[RiP]

If it's doing that, but the time is much shorter than expected, then there's probably a problem with capacitor C712 (10µF).

Unfortunately, replacing C712 didn't help too