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Board in S0 state confirmed by checking all power rails. CPU Vcore 1.8v.
Fan spins normally for 10 seconds and then kicks in to overdrive.
No display or other signs of life.
ALL_SYS_PWRGD is present 3.4V.
PLT_RESET_L is high.
No light on USB device at all.
Resistance to ground at...
Okay, trackpad replacement fixed it. No damage or corrosion to trackpad. IPD flex OK. Trackpad uses SMC "3" SMBus but was somehow interfering with the other data lines? Or HWmonitor not naming the sensors correctly?
Anyway, it's fixed, and I feel a bit silly.
Okay, Replaced Q5830, no change.
Replaced U5800 as well with no change.
I can see that U5800 communicates on SMC S0 "1" SMBus, and the camera and U5620 use that as well, and are not reporting errors. Pull up resistors are in good shape as well.
Sensors Q5860 and Q5810 attatched to U5800 are...
Logic board gets to S0 state but has generic SMC error.
HWMonitor shows that heatpipe inlet temp and heatpipe outlet temp are 128C.
Inlet temp is q5830 attached to U5800, but does anyone know what sensor or bus heatpipe outlet temperature would be? Trying to find if there is a shared...
Same. Original battery with a ton of cycles still might be more reliable than an aftermarket.
I like to try to buy original pulls that are graded A or B (for remaining capacity. Getting hard to find, however.
Sounds like I should have done that in the first place. As always, thank you for taking time to reply.
Don't have time to get a donor, had this far too long anyway and I think the customer is done with us.
Hmm.. source? I read the datasheet, and my admittedly poor understanding of the chip design makes me think that it is just a high speed capable switch, and it's outside behavior is controlled by the Dx_SEL pin on the chip.
Or do you mean that the system firmware has to have the proper GMUX chip...
I have been working off of 820-00281 for lack of the exact schematic.
I actually did replace U9850 with the TI chip I was able to get my hands on. It is supposedly compatible, and the datasheets seem to agree with that. No change, however.
Tested with a display that was previously working...
I have a touchbar mac that does not output to the internal display. I can get video output via USB C, and the logic board powers on and boots mac os.
The history is liquid damage, no obvious corrosion except between pins 1 and 43 of J8500. Cleaned up and replaced LCD cable, verified no...
Logic board had liquid damage, corrosion on U1930, and on the J6100 connector.
Replaced U1930 and removed J1600.
LB appears to be functioning normally except it throws a PPT004 battery error when the internal diagnostics are run, even with a known good battery.
The strangest bit - I accidentally disconnected SPI_MLBROM_CS_L from SPI_CS0_L and CPU Vcore and all rails stabilize, and the fan spins up full. No display out or signs of booting at this stage - which I do not expect would happen.
I will replace the flash chip next workday to see if it is bad.
I have cleaned several times in the UC with no change. I don't want to pull ram chips off to look for issues.
Could this be a system clock issue? It will option boot and run EFI diagnostics. It will even boot tot the filevault unlock screen, it tanks after it actually boots OS.
Could this be a...
So to revisit.. I have two of these with the same symptoms. Checked end to end continuity of all spi termination resistors and traces.
U6100 is getting power, U1900 is getting power.
Could the clock chip go bad?
Is this a common no fix?
820-4924 that will not boot - once the loading bar is 1/4 there are graphical artifacts in various colors and it hangs.
There was liquid damage that appeared to be minor, corrosion had eaten pin 13 of U1900, so replaced that chip, and there did not appear to be any other damage.
I have an 820-2936 that I attempted to flash firmware to with clean ME region. I used the apple 1.5MB ME version 7 since a tool indicated that the stock rom had ME series 7.
I flashed the ROM and it successfully writes and verifies, but when I turn the machine on it beeps SOS. Literally 3...