(347) 552-2258 [email protected]

820-00926 Has circle with line through it. And spots that look like dead pixels.

bjf

bjf

Member
This board had slight liquid damage in the CPU circuit area. PPBUS_HS_CPU had a damaged capacitor. No short though. The board will try to boot (seems intermittent) and will show the Apple for a second and then show a circle with a line through it. At the same time, a bunch of random pixels will light up. The pixels change each time I try to boot. It looks like about 25 dead pixels spread randomly around the screen. Nothing else happening. I haven't seen anything like this before. Not sure where to go next.
 
bjf

bjf

Member
Yeah, thanks, seems to be the case. I'm hoping for some other magic fix being that the CPU is at least doing something.

Also, I had the number wrong. It's 820-00928. 2017 MacBook Pro 15". Is someone able to fix the title for me? Not sure if it will matter as far as the outcome but it would be nice to at least get that part right.
 
bjf

bjf

Member
Yes, it displays the exact same thing on an external screen. Weirdly, before I replaced C7292 it would just hang on the Apple, but not show the circle symbol. Is there any type of fix I might be able to try or is this just done?
 
2informaticos

2informaticos

Administrator
Staff member
C7292 has nothing to do with this issue; is not really needed.
Something happened when you applied heat on that area.
Check for corrosion under microscope.
Put good flux and heat GPU, U9800 and CPU; no more than 180-200 degrees, just to burn eventually crap underneath.
 
Last edited:
bjf

bjf

Member
Ok, thanks, I'll try that. I purposely only used a soldering iron to avoid adding heat. No heat gun. The whole replacement was done in a matter of seconds. C7292 was already falling off the board so it was straightforward. I'll try to clean up those area with some flux and see if that helps.
 
bjf

bjf

Member
I checked the board again. I attached a pre-cleaning picture of the area hit (and then pictures of the whole board, also pre-cleaning). This is the only area that was hit by the spill. Underneath that corrosion, the only components that look damaged were a few smaller capacitors. I replaced C7292, and C7290 and C7293 look a little rough but are measuring fine. Is there a chance that one of these might be failing once power is applied? I've never know this to happen but I'm wondering if a capacitor could fail in this way, where it's intermittently shorting or partially shorting? I just can't find any other reason why this board is failing.
 

Attachments

  • photo2463.jpg
    photo2463.jpg
    468.3 KB · Views: 0
  • photo2464.jpg
    photo2464.jpg
    1.7 MB · Views: 0
  • photo2465.jpg
    photo2465.jpg
    1.8 MB · Views: 0
  • photo2466.jpg
    photo2466.jpg
    2 MB · Views: 0
  • photo2467.jpg
    photo2467.jpg
    2.1 MB · Views: 0
2informaticos

2informaticos

Administrator
Staff member
None of these caps are related with your issue.
You can just let them out of board.

Dead pixels spread around the screen, even on external monitor, point to GPU, or vRAM problem.
But prohibition sign should be something else.
Disconnect Lifeboat connector and try to start USB OSX.
 
bjf

bjf

Member
It's a 2018 so no lifeboat. It's also booting, or attempting to boot, intermittently now, so sometimes I can't get it to the drive-select screen. And sometimes it seems to freeze. I'm not getting to the prohibition sign much anymore. I guess the assumption is that the CPU or VRAM was damaged from the spill even though it didn't hit the CPU or VRAM directly? It's completely clean around all of that.
 
bjf

bjf

Member
You're right. I'm confused. I had a 2018 sitting in front of me when I was typing that. Letting this one go. So little liquid-damage for such a complete failure.
 
You must log in or register to reply here.
Top