820-00164a Fan spin no brain?

Yoel Ren

Member
So I have this board which came in, fan spin for 10s, stop, and then spin unlimitedly..,but still not turning on, no chime. vcore is present at 1.8v, I suspect this might be the bios is it? I have tried replacing u1900
Can I use another exact board bios, clean the me, and place it there?
 

2informaticos

Administrator
Staff member
Try new BIOS and clean ME, if you have Medusa.
Need a known good working BIOS, do not clean ME of original.
Don't forget to fix Fsys checksum, if you change serial number.
 

Yoel Ren

Member
Hi, I have 1 working 00164 board, i pulled the bios and tried to clean me, but got an error, then i just put it there at the board, now it can turn on and boot, but fan behaviour still not normal, (spin, stop, spin, should be spin stop three times), can I use any other board with similar looking bios and flash it with, maybe your bios file, if you have it?
 

Yoel Ren

Member
Hmm i think the files doesnt work, i use ch3241a + medusa 3, i have test with many chip, same fan behaviour, and no usb activity
 

2informaticos

Administrator
Staff member
"now it can turn on and boot, but fan behaviour still not normal"
You've said boot; means the board works.
I now suppose you only mean the board turns on, but don't work.

Board stays on after 3 attempts, or just cycles?
 

Yoel Ren

Member
Looks like the bios chip has been replaced before, the one on the board doesnt work too, and I have tried clean me, still same
 

Yoel Ren

Member
Hi, i bought a tl866ii plus, i tried hooking it to pomona clip fron medusa, i read the chip, erase, open clean bios file, and then program, but it still doesnt work ( no fan spin), i tried this on my known good board, if i put back original bios, it can work, i don't know where it gone wrong when programming the bios, is there any step by step tutorial?
 

2informaticos

Administrator
Staff member
If you have BIOS file from identical board, it should boot; even when ME region is dirty.
The problem there is someone else already messed with this board.
Do you know something more about board history?
 

Yoel Ren

Member
so it does boot, but without 3 fan cycle, i cannot do pram reset, but I can do smc reset, when inside the os, trackpad and keyboard doesnt work.., I have tried with known good tp & cable & keyboard
 

2informaticos

Administrator
Staff member
Check all TPAD_SPI traces and resistors.

Be aware of TPAD_INTWAKE marking; only SPLIT, or SHARED components can be placed at same time!
So remove R4844, if R4841 was already on the board.

Post U4810 voltages, in OSX.
 

Yoel Ren

Member
in osx, when trackpad cable isnt connected, I have pp3v3_s4, pm_slp_s4_l, and tpad_spi_if_en, the rest doesnt present
in osx when trackpad cable is connected, pp3v3_s4 and pm_slp_s4_l, but tpad_spi_if_en is 0.4v
 
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