820-3115 four beeps no boot

[Dmitry]

Hi there, not even sure where to start since there is no topic on internet taking about 4 beeps.

I have this mac doesn't turn on. no image, battery charged fans spins, all common voltages are at place. No water damaged. Never seen board so clean. costumer said best buy swap board for them few months ago.

I press power button, it has 4 peeps then repeats. I have tried RAM just in case.

3 short beeps and 1 little longer, then it repeats.
Any ideas where to start? I tried to plug all the flexes.

 

[dukefawks]

I suspect a corrupted BIOS. Try this one, preferably on a different EEPROM so you don't mess up the original.

https://drive.google.com/file/d/0ByfhQ_x0v-tZYy1WaGhQNTVQME0/view?usp=sharing

 

[Dmitry]

I haven't done macbook BIOS flash before. I am using TL866 programmer, I am getting an ERROR "OverCurrent Protection actions! External short circuit/IC reverse or damaged!"

I dont have other ICs to test it with. does it meen eeprom is damaged?

 

[Dmitry]

I have higher then normal resistance on EEPROM pins 3 and 8. I do get 3.3v there, so most likely bad chip?

 

[aprendiz]

FIrst check if IC is properly positioned on programmer...

 

[dukefawks]

Either chip wrong way around or some pins shorted together. MAKKE SURE YOU GET A BACKUP OF ORIGINAL CHIP!!!

 

[Dmitry]

I will look at programming part later on Tuesday.

for know I found the same donor board and took chip from there. MacBook works now (takes a little longer to post), can I just do that or something will not work? can you explain noobie. there is not much information online.

 

[aprendiz]

If you leave it like that will have ME region problems, so read the original, upload the file to a file hoster and paste the link here...

 

[dukefawks]

No, please post your original dump here and include the board serial number that is on the memory slot.

 

[Dmitry]

I have made original dump. serial number is C1MN3MY2DTY3. thank you

https://readycloud.netgear.com/client/dllink.html#t=065zkxsqxlb/This one .BIN

 

[dukefawks]

Try this one, not 100% sure it will work:

https://drive.google.com/open?id=0ByfhQ_x0v-tZZ2dCMHVGOWMtU2M

 

[Dmitry]

I cant program it, getting error 0x00101B Buf_Val:0x3C IC_Val:0x1C Ive tried all I can. not sure, what to do.

I saw people sell those chips programmed on ebay, will that work or I still will have ME regions issues?

like this one http://www.ebay.ca/itm/BIOS-EFI-Fir...130290?hash=item3acbca36b2:g:rQ0AAOSwMgdXzav2

 

[dukefawks]

TL866 programs these chips just fine. Try another chip if you have one. I have no idea about this Ebay chip, but I would not trust them.

 

[Dmitry]

I finally programmed it, however that didnt fix 3 beeps issue.

 

[aprendiz]

3 beeps is RAM failure, try 1 slot at a time, usually the closest to keyboard is bad..........

 

[dukefawks]

Oh and now it is 3 beeps......??

 

[Dmitry]

Sorry, it is 4 beeps. I typed it on autopilot. I ordered pre programmed chip from ebay, should be arriving soon.

 

[dukefawks]

It will probably have a used ME region, so the board will run slow or not fully boot. You really need to program your own chip for this.