ThisIsWes:AASP
Member
Replaced j8500 and u9850 (again) and all is good.
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820-00281 u9850 keeps shorting
- Thread starter ThisIsWes:AASP
- Start date
ThisIsWes:AASP
Member
welp.. thought it was good but its not.
Boots to boot menu and install media. Will even install OS without any issues. but when finished and loading OS it gets to about 75% and the display cuts out. Otherwise, the mac is still on. "Built in screen reader" prompt is heard.
Boot from eternal is the same result. Safe mode work though.
What could this be?
Boots to boot menu and install media. Will even install OS without any issues. but when finished and loading OS it gets to about 75% and the display cuts out. Otherwise, the mac is still on. "Built in screen reader" prompt is heard.
Boot from eternal is the same result. Safe mode work though.
What could this be?
Last edited:
ThisIsWes:AASP
Member
Checked pull up/down resistors around u9800.
GFX_SELF_THROTTLE - 80k instead of 100k
DP_T_SNK1_HPD_EG - 82k instead of 100k
Removed u9800 and they stayed the same. Tested off the board and they were good.
Replaced u9800 with donor and new u9850.
Same result.
GFX_SELF_THROTTLE - 80k instead of 100k
DP_T_SNK1_HPD_EG - 82k instead of 100k
Removed u9800 and they stayed the same. Tested off the board and they were good.
Replaced u9800 with donor and new u9850.
Same result.
External video OK?
Did you try another LCD assembly?
PRAM reset done?
BTW, high value resistors measured onboard, always give lower readings as normal...
Did you try another LCD assembly?
PRAM reset done?
BTW, high value resistors measured onboard, always give lower readings as normal...
ThisIsWes:AASP
Member
External video is good.
yes same result with different displays.
pram - no change.
I understand the values are different but on other boards I’m getting 98k-100k on these.
Seems to have something to do with how the OS manages the display? I even tried going back to Sierra as I know the processes run through the GPU in HS.
Also, tried disabling gpu with Medusa as I do on 820-2915.
yes same result with different displays.
pram - no change.
I understand the values are different but on other boards I’m getting 98k-100k on these.
Seems to have something to do with how the OS manages the display? I even tried going back to Sierra as I know the processes run through the GPU in HS.
Also, tried disabling gpu with Medusa as I do on 820-2915.
Medusa can do that for 2914/15 only.
Put back original BIOS, or another known good file (clean ME).
Can you boot USB Windows/Linux Live?
Put back original BIOS, or another known good file (clean ME).
Can you boot USB Windows/Linux Live?
ThisIsWes:AASP
Member
Already put back. Will try another BIOS file.
I don’t have a bootable for those.. it does boot into installers and in safe mode so I would assume so. In safe mode the GPU is shown in system report fwiw.
I don’t have a bootable for those.. it does boot into installers and in safe mode so I would assume so. In safe mode the GPU is shown in system report fwiw.
Aaaa, it boots macOS in safe mode.
Installing fresh Windows can help you.
If finish the installation, start to install drivers and see when it crashes.
Installing fresh Windows can help you.
If finish the installation, start to install drivers and see when it crashes.
ThisIsWes:AASP
Member
When connected to external, in system info under graphics/display the display is not recognized. In safe mode it is.
it seems the OS isn’t communicating with the display. Similar to how keys can work in boot menu but not in the OS?
if this doesn’t reveal anything I’ll try Windows.
it seems the OS isn’t communicating with the display. Similar to how keys can work in boot menu but not in the OS?
if this doesn’t reveal anything I’ll try Windows.
ThisIsWes:AASP
Member
Replaced disp connector - no change.
Any ideas why the OS isnt recognizing the display??
Any ideas why the OS isnt recognizing the display??