820-2850 - not turning on after changing C9560

[Alan.L]

board was working fine. but keyboard was liquid damaged, somekeys didnt work. so i changed the keyboard. so i thought might as well change C9560 while the board is out.

after i changed C9560. now the board doesnt boot. the cpu does get warm and fan doesnt spin, mouse get red light. no video.
it see the battery, can charge the battery.

pin1 of C9560 is now shorted to GND. even i remove this cap, pin1 is still shorted to GND.
pin1 and pin2 of L9560 is shorted to GND.


PPBUS_G3H 12.57v
PPBUS_CPU_IMVP_ISNS 12.57v
PP3V42_G3H - 3.413
PP5V_S5 - 5v
PP3V3_S5 - 3.3
PP3V3_S0GPU - 3.3



did i killed the cpu or gpu??

 

[rany]

What is the resistance in Ohm reading? And did you try a different cap?
I've replaced quite a bunch and never damaged anything. Were you blowing hot air inwards towards the board or outwards?

 

[dukefawks]

Did you use hot air? Find the short, inject voltage and see what heats up.

 

[Alan.L]

I did loads before and never had problem. Yes i used hot air. Yes i've tried another cap.

Ok i'll inject voltage

 

[Alan.L]

pin2 of L9560 pin show 1.554v and pin 1 show 1.57v - can this be the culprit?
pin1 of C9560 show 1.554v, pin2 show 0.001v

before i inject voltage...how much voltage should i be injecting?

 

[dukefawks]

Uhm, I have no idea what you are doing. But if the board is powered on and there is 1.55V on C9560 what is the problem?

Please also explain to me why 0V on pin 2 of C9650 would be fine?!

 

[Alan.L]

0v on pin2 is gnd. i just telling you incase you needed to know.

pin1 is shorted to GND when there is no power. but when i plug magsafe, pin1 of C9650 show 1.55v

 

[dukefawks]

So power is fine on the rails.
If you get a light on the mouse the board is working. Do a PRAM reset and see if you get a chime.

 

[Alan.L]

i did a pram reset, still no chime and fan doesnt move.

yes pram reset goes from green then orange then green with magsafe+battery.

what should i check next?

removed ram, doesnt beep.

 

[Alan.L]

What is the resistance in Ohm reading? And did you try a different cap?
I've replaced quite a bunch and never damaged anything. Were you blowing hot air inwards towards the board or outwards?

resistance on pin1 of C9560 is 125 ohm. blowing outwards


resistance should be roughly 600 ohm right?

 

[dukefawks]

125 is fine. This could be anything if it doesn't beep without RAM. You damaged something, no way to tell what. If fan does not spin there is no way there is CPU Vcore or a light on the mouse. I have no idea what is going on here.

 

[Alan.L]

i need another 2850 to compare with. i get back to this board once i got another one. thanks duke