820-2936 Fan turn on and off cycle.

[Dewanbd]

This unit shows green light , fan spinning and off , cycle. Looks like no liquid damage.
Green Light - OK
PPBUS_G3H - 12.58v
PP3V42_G3H - OK
PP5V_S5 - 5v ok
PP5V_S0 - 5v and drop for 0v (turn on and off fan)

Y2805=1v

Removing memory turn on fan continue running and no memory beeps sound.

 

[2informaticos]

When machine boots, VCORE should drop to 0.8V aprox.

Seems like something goes wrong when CPU starts to work.
Doesn't spin the fan in SMC bypass at least?

 

[Dewanbd]

When machine boots, VCORE drop to 1 V and machine fan stop it drop 0V.

Doesn't spin the fan in SMC bypass, at all.

 

[2informaticos]

"boots" I mean machine working.
You reffer to turning on, which is not the same.
If VCORE steady 1-1.15V, no good; you must note a small drop, until aprox 0.75-0.85V

If board turns off with RAM and stay on without RAM, should be some issue with CPU, or PCH.
Bad communication with RAM is still possible.

 

[Dewanbd]

Re flow CPU /PCH , now fan is spinning and boots normal. FIX!! Thanks.

 

[Dewanbd]

After 3 days there is no display, turn on,hear chime sound , see the screen light on but no display. Any help please?

 

[JohnB8812]

Rehot CPU is not a solution lol likely just heated dead chips and they worked for a few days. This board is junk

 

[Dewanbd]

Chance bios and now it works, dont know why.