tcampbell34
Member
I have a 820-00850 board that came in and was not turning on. When I tested it, it would boot up to 20v 700ma for only about 15-20 seconds and the fans wound spin at normal speed for about 2 seconds then stop. Nothing on the screen. Then the board would seem to turn itself off and go to 20v 0.03a. The board looks very clean, but I did find some small corrosion in the CB565 and QB660 areas. The pad for pin 1 of CB565 was burnt and destroyed so I have left that off the board. I cleaned the corrosion and replaced a few caps and resistors around QB650. I also replaced QB651, QB660, and QB QB650. Was still getting the same result after this so I tried a T2 firmware restore but that failed and now the board will only boot to 5v 0.07a unless I do another T2 firmware restore. I did notice during the firmware restore, the board goes back to 20v 700ma for a few seconds and the fan spins for a second or 2 again, but then I get an error in apple configurator and the board now only shows 20v 250ma and the fans spin at full speed. I have attached a screenshot of the error. The board will only stay like this for about 2-3 minutes and then the fans turn off and the amps drop to 0.03. If you unplug the charger and plug it back in, it will only go to 5v 0.06a now. The rest of the board looks spotless so not sure where else to look. I took some measurements while the board was using 700ma and it appears to have all voltages including CPU voltage. Also took measurements while the board was using only 250ma and high fan spin and it looks like its only in S3 state. Any help would be appreciated.
20v 700ma | 20v 250ma | |
PP1V8_S3 | 1.8v | 1.8v |
PP1V8_S3_MEM | 1.8v | 1.8v |
PP1V_S3 | 1v | 1v |
PP1V2_S3 | 1.2v | 1.2v |
PPVCC_S0_CPU | 0.95v | 0v |
PPVCCSA_S0_CPU | 1v | 0v |
PPVCCGT_S0_CPU | 0v | 0v |
PPVCCEDRAM_S0_CPU | 0v | 0v |
PPVCCIO_S0_CPU | 0.95v | 0v |
PP1V2_S0SW | 1.2v | 0v |
PM_SLP_S3_L | 3.3v | 0v |
PM_SLP_S0_L | 1.8v | 0v |