820-4924 3 beeps as in ram problem

[2click]

Hi, I have this board beeping 3 times

Voltages on U7400
6= 1,8
12= 5,1
16= 3,3
17=3,2

This board was messed with before, because it had a short on the line PPDDR_S3_REG_R caused by a bad resoldered ram, I changed the 4 chips, but it is still giving me the 3 beeps...
I messed up a little with the ramcfg resistors but put them back again...

 

[2informaticos]

If all chips have good solders, then a bad RAM chip, or CPU.

 

[2click]

I reflowed the ram and now it is turning on, but the fan is going hi inmediately, I changed the smc, but made no difference... what sensor makes the fan go high?

 

[2informaticos]

Try first disconnecting webcam.
Next, change trackpad board/flex.
Also try known good RIO board/flex.

Run HWMonitor and check for strange temps reported.
You can make an idea about which bus is affected.

Starting in diagnostic mode, can also display usefull information.

 

[2click]

reballed the smc and that did it... thank you for your help!