820-3435 .74A then .54A then OFF

2click

Member
Hi, this board tries to start, goes to .74A a couple seconds and goes down to .54A and then it shuts down and repeat the same over and over again. I checked the board for corrosion and found corrosion on R6102, I cleaned it on the ultrasonic and had to change R6102 after doing that, now it is having the same behavior.
What should I check first?

Happy New Year!
 

2informaticos

Administrator
Staff member
Check ALL SPI Bus Series Termination resistors and their traces.
Clean/remove J6100.
Reball SMC, as usual for corroded boards.

Does it start in SMC bypass mode?
 

2click

Member
I reballed SMC, j6100 is clean and SPI Bus Series resistors have correct values and look OK. Still not working properly. On PIN 1 R6115 getting a pulse when turning on, but only a pulse of around 1v and then goes back to 0v.
I was thinking about reprograming BIOS, I have a TL866Plus but can´t read the BIOS on that programmer or maybe I am doing something the wrong way... Does that bios need different programming ?
 

2click

Member
I got a u6100 from donor, but still can´t read it on my TL866, is it. different from other bios chips? I put other bios and can read them with no problem, double checked the soldering pads and they were ok. Don´t know what to do anymore...
 

2click

Member
When trying to start it in SMC bypass mode it does the same, but the backlights turns on for a couple seconds and then turns back off but this time doesnt loop, it stays off.

update: I was turning it on without the hard drive, with the hard drive it turns on, get to the login screen for around 10 seconds and shuts down... Changed the cpu thermal paste, same behavior...
 
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2click

Member
It turns off in the boot menu, it shows me the hard drive to boot of around 10 seconds, the same that in login screen and it shuts down, the BIOS is the original and the problem is that I cant read the BIOS chip in my programmer...
 
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