820-4924 NO brain? Water damage

[djdblaster]

Orange light, chimes, backlight on, no picture.

The battery had no juice, I plugged the charger for few seconds then unplugged it. The screen showed "battery charging symbol" which concludes pictures is there after all, the screen is good.

Inspected motherboard for visual signs, found water damage around Q7630, C7260, C7622, C7624, L1295, C7630, R7631. Basically around that area.

PPBUS_S5_HS_COMPUTING measures 0.115 diode mode. (or correctly saying Threshold Voltage, I guess.) Isn't that too low for that rail?

I suspect computer never really turns on fully, so no brain issue?

 

[2informaticos]

Forget about power rails, all are good if you got image!
You may check SSD power, just in case.
I recommend to start booting from OSX pendrive; let see what happens.

 

[djdblaster]

Alright, I’ll first replace a couple of bad looking components, mentioned above, and report back.

If SSD power is not good, should I get to Question Mark screen eventually after a minute from starting laptop?

 

[djdblaster]

Well, tried OSX pendrive, it boots. Tried another SSD, it shows a question mark (it's empty), so that's good.

Bad news I guess - bad SSD. Repairable?

 

[2informaticos]

Disk Utility recognizes that SSD (maybe not formated)?
If yes, try to format it, if no data needed...

 

[djdblaster]

I'll try that.

I took measures from both drives when connected, bad drive pulls 2 signals short (pins 30 and 31)

Good SSD:
Pin 30 - 0.337
Pin 31 - 0.342

Bad SSD:
Pin 30 - 0.018
Pin 31 - 0.019

 

[2informaticos]

These lines are for 100MHz clock, so should be tested with o-scope.
Bad SSD is almost 0V, because oscillation is not present I suppose.
Do the mentioned test first.

 

[djdblaster]

Currently, I have not way of testing it. I see that the computer doesn't want to display anything when bad SSD is connected. As said, it chimes and gives backlight, but that is. With good SSD, it works.

When measuring pins on SSD itself, they show 0.018V instead of 0.335V. Is there a way to repair SSD itself?

 

[2informaticos]

Access boot menu and choose USB pendrive with OSX, but let internal SSD connected...

 

[djdblaster]

Doesn't work. I'm holding Alt key, no image on screen, just backlight works. It's stuck with bad SSD.

I plugged OSX pendrive in case it boots directly from it, but nothing. The pendrive doesn't flash.