820-3437 chimes, bklt comes on no video

fijolin

New member
No liquid hit the board, ever.

Chimes, backlight comes on but no video.
Mouse lights up after a while but shuts down after a while too.

Bios replacement didn't help.

Customer said that prior to no video at all it would shut down randomly.

No pic to external either obviously.
All powers present including cpu vcore etc.

Any ideas?
 

2informaticos

Administrator
Staff member
Can you confirm USB activity?
USB mouse can trick you, use the other method; many-many times explained on the forum.

Did you try PRAM reset?
Internal LCD stays black, or white?
 

fijolin

New member
This particular mouse has always been "right" about usb activity.
But FAIAP, tell me more about the other method, I'm a regular reader of
this forum but I still didn't find it. Tried searching for it here also.

PRAM reset done.
Internal LCD stayed black.

EDIT:
I left the machine on the black screen for a long time, surprisingly there was a questionmark when I came back.
Now it boots but veeery slow. Starts booting Os but doesn't finish.

Has a known clean rom. Will try replacing the rom again I guess...

Could a bad memory cause something like this? If it's sort of going bad little by little?
 

fijolin

New member
First rom was from ghostlyhaks.
It was supposed to have clean ME etc., (didn't check myself to spare time, maybe should've).

Tried a rom from the myth himself, Duke.

Needless to say, booted up perfectly.

My guess is that the old bios chip went bad overtime (although I know it's more usual on 820-00165 boards).
Maybe others have had 3437 bios' fail more often, this was a first for me.

Thanks for all input!

Just out of curiosity, is there a way to modify the bios to accept apfs without installing high sierra etc
on the donor bios first?

Now I have to install something on the fixed machine in order to get it to accept apfs based Os x...

EDIT: And yes, I changed the serial on the rom from Duke.
 
Last edited:

2informaticos

Administrator
Staff member
Did you also fix checksum after serial was changed?

You need a BIOS with APFS support from other board, clean ME, change serial and fix checksum on it.
Is more easy to do new installation on a test SSD.
 

fijolin

New member
Didn't have to, Duke already did that.
Otherwise, sure thing.

That's what I feared with the apfs compatibility.
 
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