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820-00875-a - a1708 - frying SSD'S

Anterweb

Anterweb

Member
religion = region stupid auto correct!

Gotcha yes, I see that centre pad now, So I need to solder onto the adaptor card.

Do I ask here for the bios dump or should I start a new thread ?
 
Anterweb

Anterweb

Member
Thanks a zillion for the dump, please excuse my ignorance on this but using this bios adaptor is a first for me, where are you putting the kapton tape?
 
Anterweb

Anterweb

Member
So I have the bios chip removed and soldered to the adaptor. It recognises it and let me erase the chip, Then when I click blank check I get this

Current programmer: CH341
15:54:35
Verify memory...
Verification error on address: 00140000
Execution time: 00:00:11


and if I load the bios dump you gave me and hit programme I get this error

Current programmer: CH341
15:20:35
Programming memory(verifying)...
Verification error on address: 00000010
Execution time: 00:00:00

Just thinking about this I'm using the ASProgrammer software in windows 11 , could this be an issue?

Im using ASProgrammer Verison 1.4.1
 
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Anterweb

Anterweb

Member
I removed the chip from the adaptor then soldered it back on and Asprogrammer seemed to prefer this, It read and erased the chip but again would not programme IC, So I tried anther software SiberiaProg_CH341A, This read, erased and programmed the chip and when verifying it told me the chip data matches that on the buffer screen of the bios dump you gave me,.

So I solder the chip back to the board and put the mac back together

Now I turn it on I get trackpad click but no fan spin and no display,.

As this is the first time I have done this i'm wondering if I missed a step somewhere or is there something I need to do when turning on the mac now it has a new bios?

Amy help much appreciated
 
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Anterweb

Anterweb

Member
I have tried to download the file but it said I need to wait for an email confirming access to the drive.
 
Anterweb

Anterweb

Member
Got it thanks, Used it to flash the second chip I have here and same result, Mac feels like its turning on I feel the touchpad turn on and give clicks and after a few mins I can feel the cpu getting warm but just a blank display, Tried forcing an external display, Nothing,
I don't have much confidence in this programmer/software I have here. I'm going on holiday tomorrow afternoon so if I'm no further forward with it by then Ill ask a friend to programme 2 chips for me with each of the dumps you have posted and try them on my return next week.
 
Anterweb

Anterweb

Member
Shit I've just realised, the serial on this donor board is different from the one in this thread title, it's a 820-00840-A

Is this what's given us the issue with the bios dump?

20220409_091845_remastered.jpg

Here is the board info, I just tried a bios I found on the bad caps forum but this just gave me no screen no trackpad click, so it's deffinatly a bios version issue
 
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Anterweb

Anterweb

Member
Just back from holidays, I got a brand new chip with the above bios dump put onto it for me and it worked perfectly as soon as the chip was put onto the board, SO thank you so much for that,

One odd thing I noticed is that this machine now see's and has installed an OS onto the original apple SSD's that I was convinced were dead from the last logic board. Strange

Thank you for all of your help on this one. Ur a ledge!

( Now I need to find a bios programmer that works )
 
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