On Thu, Jan 19, 2023 at 10:44:09AM +0100, Andreas Grapentin wrote:
On 19. Jan 2023, at 10:06, Andreas Grapentin andreas@grapentin.org wrote:
I started looking at the micro desktop board with my multimeter and did some checks, but it’s difficult without reference to a known good board. But what is maybe noteworthy is that of the three larger capacitors on the board just behind the power socket, both sides of all of them are connected to ground. I assume that part of the board is responsible for the power control? If so, then the small chip in the middle might be blown. Again, hard to verify without a known good board.
I found the schematics for the micro desktop, and was able to take a closer look. I tested around the RT8288A, and noticed that pins 1, 2, 3 and 8 have basically zero resistance to ground. That’s not good.
I’ll get a hot-air solder station and a microscope, and get that chip off the board, then do some more tests to see if the other components around that area are okay. It could also be that one of the capacitors nearby is blown.
I’ll try to get this micro desktop back to working order, because I have the suspicion that the power issues of the micro desktop are causing the boot loops, and I don’t want to break anything else :)
So we have two "active" testers with a broken micro desktop each. This is the thread where we discussed my power problems and the blown RT8288 in 2020 (see attachment and Lukes replies in the thread [a redesign of this area for micro desktop 1.8] and a schematic as attachment):
https://lists.phcomp.co.uk/pipermail/arm-netbook/2020-July/016353.html
Andreas, Do you want to accept Lukes offer for one of the five precious micro desktops? If you are done with your testing, you could send it to me. I am curious if my Computer Card is still working.
Pablo