820-00840 no video

[prodigy83]

My Reference only: Ticket # REF1124.

Board has liquid damage. I was getting video prior, now I am not getting video. The board is heating up. There is quite a few audio sections that got burnt at some point but I would imagine this has nothing to do with the video?
R3453 Pin 1 in diode mode reads 2.235. This area the diode (d3452) next to it I had to repair the traces. I get no voltage coming through.
r7140 pin 2 is 3.3
r7155 no voltage
r1501 and r1503 no voltage
q1930 1 and 2 pin no voltage

 

[2informaticos]

Q3450/60 vias don't work at same time; depends which port the charger is connected.
If USB-C meter switches to 20V on both ports, there is no problem with CC1/2 pins, or something else on USB-C area.

"r7140 pin 2 is 3.3"
Then CPU core is present; what's the voltage after 10-15s?

 

[prodigy83]

Then CPU core is present; what's the voltage after 10-15s?

At first pin 2 is at 3.3, then after 15 or so seconds, it drops to 0, then it went back up to 3.3 after another 10 or so seconds.

Don't know if this is relevant but I also get NO voltage on CPUVR_FB_R_3 at all.

 

[2informaticos]

Try again, checking CPU core voltage at pin 2 of L7210; you can't get 3V there.

 

[prodigy83]

I am getting pulsing anywhere from 0v to .05v.

Try again, checking CPU core voltage at pin 2 of L7210; you can't get 3V there.

0v

When I try to chase this backwards, I do get 3.4v at SMC_CPU_ISENSE, but next down the line CPUVR_ISUM_IOUT I get 0v. Thermal cam shows the areas it is heating up at when plugged in.

 

[2informaticos]

Is U5600 soldered on the board?
If not, don't bother with that area.

Seems that you don't get CPU core voltage at all.
Do you get voltage at L7730 and L7370?

 

[prodigy83]

No U5600 is not, however I decided to check pin 5 in diode mode and noticed it is supposed to be .351 but I get .402.
Moving on...

Do you get voltage at L7730 and L7370?

L7730: 1.053
L7370: 1.048

 

[2informaticos]

There may be accumulated crap underneath CPU.
Try to heat with quality flux.

 

[prodigy83]

There may be accumulated crap underneath CPU.
Try to heat with quality flux.

No go. This board does have a bit of audio lines (Speaker Amp according to schematics) that have been burned, but they all seem to be at the proper voltage. Like around C6464.

 

[2informaticos]

I suspect bad CPU on this...