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I dont have another keyboard yet, however I have a fully working motherboard of a 820-3476 and it produces the same issue. It could be the connector too not 100% sure however keyboard itself looks really good, no obvious signs of water damage yet original board did have some.
Update: Got my hands on a file, however this was misdiagnosed.
I flashed a new bios and discovered the keyboard is not working properly. 5, T, H, and Space do not work. As well as E, D, C, and left command, hence why PRAM reset wasn't working.
Does anyone know what keys respond to what...
Symptoms are will turn on, in a constant bootloop, chime every 3 seconds. SMC reset does work but nothing changes, PRAM reset does not work. I cannot find any 820-3536 files online, only 3476, are they the same??
Inspected board and some corrosion around U7200, and J6100...
820-00426, symptoms are all power rails are present, board alone takes a little over an amp, and slowly rises
CPU and GPU VCORE all present, as well as clean ME and reflashed BIOS chip, USB lights up but no activity.
Im leaning this towards a dead cpu, however I just want to be sure. R to G on...
You are right, misdiagnosed onoff reaction, as it reacts to it as the power button, hold for more than 5-6 seconds to have effect.
thank you once again
Also it does not always boot into bypass mode, just sometimes, especially when I leave it in macOS running for some time.
Looking into U5800...
SMC_ONOFF is a constant 3.42V, even when pressing power button.
No pulse on PM_BATLOW when triggering SMC_ONOFF by power button and tweezers manually.
No change in reaction with LIO connected or disconnected.
EDIT: fans run high and macos boots into safe mode sometimes, checked hw...
820-00165, history is weird, however came to me with dent in charger port, and it looks like some charger port water damage too. Owner said she brought it to apple and they diagnosed it as a bad logic board. Board will boot in safe mode on its own sometimes, and fans will spin to max.
Im going to end this post, as now im noticing all_sys_pwrgd is shorted, pin 1 of u1950 is not connected to all_sys_pwrgd, which it should be, its not going to ground either so, too many broken traces, wouldnt sell this to anyone even if fixed, Ive found 10 broken traces already. Thank you...
3v3 sus is present everywhere, as well as pm_slp_s4, s3, and 5v_s0. I narrowed it down to u7600, pin 13 is 0V, whole circuit looked fishy so I replaced almost all resistors and capacitors, and u7600. However still same issue. I noticed pin 13 was 0v but r7601 was 5v. Checked continuity and there...
Scratched pin 8 down to just board, then filled with coating, but not over the small hole I made. Pin 8 was fully free, not connected to ground, or anything, then I soldered a wire from pin 5 of U8130 to pin 8 of u6100, and yay we now get 3.3v on the spi chip. However still same 94 mah.
max my psu is taking is 1.38v at 4.5 amps.
I injected it on for a straight minute, 5 times, grabbed all parts, and touched all parts of the board, and not one hot spot.
The things that get hot are my injection probes, thats it.
Could this be a broken trace?. Like a leakage to ground?
my fault, by run a wire I mean destroy the pad and then run a wire to pin 8.
injection of 3.3v to that pin skyrockets it to more than 4 amps.
1.0v takes it to over 3 amps. however pch doesnt get hot.
edit: Im struggling to find anything getting hot when injecting voltage.
Board takes around 88-94 mah, and stays.
No liquid damage signs but it looks like its been ultrasoniced before.
Ive seen boards with no spi rom act sort of this way, so I measured U6100. Noticed immediately PP3v3_sus was shorted to ground and 0v, though nothing was getting warm, pch...
Finally, I had to order more solder balls to reball an donor board cpu, but board is working now. I reflowed CPU and PCH first and still same issue, so I pulled the CPU and I noticed some of the solder balls were just weird looking, or partially missing. Going over it with the soldering iron...
1.5 M ohms at Pin 3, good working board is reading about 9 M ohms
2.5 M ohms at PM_PCH_SYS_PWROK, working board is at around 9 to 9.5 M ohms
Should I try to inject voltage at R1962? Or is that an actual signal not a solid voltage?
Yes, I replaced R1950 too just to be sure. Replaced U1950 the second time just to be sure, and removed R1962, and got 3.3V on Pin 3, however when putting the resistor back on I get a solid 0.000 now :unsure:. Im confused on this one.