Bricked a 2015 A1502 820-4924, brdview?


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3 years 1 week ago #7171 by neighborhoodguy
Hi All, I have an A1502, the 820-4924 (emc 2835) board, was having hard time getting chip detection, and I ignored my spidey-sense telling me to pull the chip instead of continuing, (of course lol) finally figured out power issue and got reads and writes, reflashed, and.... nothing.

Turns on and off from power button, but no post/chime and no video or fan. Measured rails, all S0 present I think.
If I do smc bypass start I have fan, but still no chime and no video. Again all voltages appear present....
I think all rails are present but I need the boardview file to be sure. Unit was making it to folder symbol before, although sound was rally low and fan seemed to not work. Unit is of unknown origin.

Does anybody have the boardview? I attached the schematic...

I get by with logicboard repair, better with power rail issues then chipset signals... So, any ideas?

I sort of remember the older ones would act like this with an empty rom, but not sure...

I use a ch341a. Thanks to a friend I learned that on 2015 a1502, a1465 and a1466, connect magsafe to turn on, hold power btn to turn off and keep it held, erase and program while holding pwr button. Tested working on all 3 models. Holding pwrbutton down gets pp3v3_sus_fet up, which you need to power chip.
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3 years 1 week ago #7172 by neighborhoodguy
hmmm, pulled clean dump from repo, flashed it, then with it sitting there - just board, magsafe conector and fan with usb keyboard plugged in, I plugged in magsafe and ignored it. Few minutes later I noticed fan spinning (which wouldnt do before without smc bypass). So I press capslock on keyboard (classic post test) and Joy!!!

This thing took a long time to boot before I killed it, maybe I should clean ME regions.

Thanks for being there to listen lol,
If I can help you with this model, please ask;
I seem to have talked myself thru it

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3 years 1 week ago #7174 by neighborhoodguy
I was right, bad ME region (pic)
I fix, I flash, I boot to chooser :)

Thanks again for the excellent ME tutorial elsewhere on this site!!!
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The following user(s) said Thank You: nebula

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