MacBook 820-3437 mag lights/fan spin/no chime

[felixthecat]

Hello all,

This may seem to be very weird, but I repair daily liquid damaged MacBooks and never have an issue. Now after all this time, I get an A1466 with no liquid damage and all signs and rails show there shouldn't be a problem. Just not getting chimes and I plug in a mouse and it just blinks popping on the mag safe and the fan immediately does what it's supposed to do, but after second spin on the fan, the CPU gets so hot you cannot even touch it. I have reprogrammed the BIOS, reflowed the SMC.....

I'm at a loss and really confused, I know I am probably missing something really stupid

 

[2informaticos]

VCORE level?
Check the other big coils voltage too.

Force the board off and check if CPU still gets hot.

 

[felixthecat]

vCore and coils steady 1.68v and forcing the board off CPU doesn't stay warm.

 

[2informaticos]

"CPU gets so hot you cannot even touch it."
I hope you have correct heatsink and fan.
Apple boards are (usually) capable to boot and show image (for short time) even without heatsink.
But I do not recommend to force CPU.

Do you get PLT_RESET_L?
Where did you get new BIOS?

 

[felixthecat]

I am talking about with the heat sink on. I learned my lesson 2 years ago on a Mac Logic Board especially these, not to run them with out the heatsink as it will damage (which happened in my case) the CPU.

As for you saying "not recommend to force CPU", I am sorry I worded that wrong as I was following your instructions to force turn off the board and check if CPU still stays hot which it doesn't. My apologies for wording that all wrong.

PLT_RESET_L shows 3.33v turning on and off

BIOS is same BIOS I use for the Logic Board with Clear ME for all repairs of the model Logic Board.

 

[2informaticos]

"PLT_RESET_L shows 3.33v turning on and off"
Do you mean PLT_RESET_L is high when board is off???

 

[felixthecat]

PLT_RESET_L shows 0v with Logic Board plugged in and turned off
PLT_RESET_L shows 3.33v pulsing on and off with Logic Board on

 

[2informaticos]

Check all SPI Bus Series Termination resistors and traces.

You may have bad CPU, if gets very hot in seconds, with heatsink installed.

 

[felixthecat]

I was afraid you were going to tell me that LOL.

Maybe I'll get lucky and hopefully find bad resistor in the SPI, if all that goes well, then I guess I will call the board dead =-/

I will let you know how it goes. let me get to probing the SPI.....

 

[felixthecat]

CPU is fried. Oh well, onto the next coffee damaged one that came in this morning. Go ahead and mark this closed please.