820-4924-A Water Damage, MG light ON, No fan

[MaxFix]

Hello,

Water damaged.
Corrosion around J7050. Replaced C7060 C7050 C7135.
Explosion C7435 (DDREG). Pad under pin 1 destroyed (see attached picture). Jumper to C7382.
C7435 is connected to U7400. U7400 all pin 0V

PPBUS_G3H - 12.6V
3V42 - 3.42V
SMC_RESET_L - 3.11V
PP5V_S5 - 5V
PP3V3_S5 - 3.3V
PP5V_S3 - 0V jumps to 2.45V when connected to power
PP5V_S0 - 0V when power ON jumps to 3.38V for a fraction of a second

Please advice how to proceed.

Thanks!

 

[2informaticos]

If you note pulses at 5V_S3/0, check if all big coils pulse at same time; L7430 in particular.

C7435 is not connected with U7400, but Q7430.

 

[MaxFix]

No pulse on any of the big coils. Only L7130 shows 12.6V on pin 2 and 11.5V on pin 1.

 

[2informaticos]

"PP5V_S3 - 0V jumps to 2.45V when connected to power
-----------------
No pulse on any of the big coils"
That is really impossible, believe me; 5V_S3 is located at L7520...

Please provide accurate information, or we cannot help.

 

[MaxFix]

I'm sorry I gave false information in my previous post (used a wrong charger).
L7520 - pulse around 3V
L7430 - pulse around 0.5V
L3095 - no pulse
L7320 - no pulse
L7310 - no pulse

 

[2informaticos]

What about L7630?
If also pulses, then check for pulse at ALL_SYS_PWRGD too.
Trigger SMC_ONOFF_L several times; you can catch higher pulse...

 

[MaxFix]

L7630 - pulse random from around 0.5 to 2.5V
ALL_SYS_PWRGD - pulse random around 0.4V to 1.97V

 

[2informaticos]

Should be better to use an o-scope; L7630 peak pulse must be 1.05V at pin 2.
Also check for pulse at U1950 pin 7.

Did you try SMC bypass mode?

Don't worry about fan.
It will not spin until CPU gets really hot.

Check for corrosion on other areas.
Should be good to reball SMC also.

 

[MaxFix]

L7630 is max 0.63V on pin 2. Dont own an o-scope unfortunately.
U1950 pulse around 0.7V
SMC bypass does nothing.
Check for corrosion in other areas again but nothing new detected.
Reball SMC is my last option? Need to order stencil in that case. Use solder paste or balls?
THanks!

 

[2informaticos]

Use solder paste; many videos available on Internet.