Something happened on the ultrasonic process.
Check for knocked off components, or broken traces.
Check for knocked off components, or broken traces.
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820-00928 No power, 20v 370ma
- Thread starter tcampbell34
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tcampbell34
Member
Yea I know but I have already checked for knocked off components and broken traces and I did not find anything. I have a Crest ultrasonic cleaner that I use all the time without any issues, so I don't think the UC would have broken any traces.
tcampbell34
Member
I got around to finally replacing the PCH on this board and now I have got CPU Vcore back but its stuck at 1.1v and no GPU Vcore voltages. Is it safe to remove UA600 from the board and try and turn it on without this chip just for test, or would that cause some kind of damage?
Do NOT do that.
Never-ever let an high-side MOSFET with floating Gate on air!!!
Never-ever let an high-side MOSFET with floating Gate on air!!!
tcampbell34
Member
Yea I figured that was not a good idea, which is why I asked first. I replaced UA600 one last time with a new one and then I put the board through the ultrasonic cleaner again because it was covered in flux and then let it dry over night. To my surprise, now it is turning on a gives me an image on the screen but it has vertical pink and green lines across the screen. I tried a clean ME bios and PRAM reset, since I replaced the PCH, but that did not fix the issue. Diagnostic reports no issues found, but if I try to boot to the internal SSD, it loads halfway and then kernel panics. If I try to boot to a external copy of macOS, it looks like it fully boots because the keyboard backlight and touchbar become active and work, but the screen still shows an apple logo with the progress bar stuck. I had a board like this a while ago and I actually fixed it by replacing the GPU VRAM chips. Is there a way I can figure out if its the GPU VRAM or the GPU itself that is bad?
Can be crap under GPU, or VRAM chips; ultrasonic bath not always clean all.
But can also be a corroded resistor, or trace.
But can also be a corroded resistor, or trace.