[SOLVED] 3787 no PPBUS, burned DC Jack

[down1nit]

No corrosion found, though I did find some crusty milk like stuff near ssd connector. DC jack has obvious carbon scoring. Replaced, now get amber light but only pulling .2A on 18.5V supply. Same on 85W genuine known good adapter.

Found PPDCIN not getting past dual Q7180. AGATE voltage on left side is 15 volts, shouldn't this be brought down by u7100? CSON jumps.

I've never had to do the logic chain stuff on the retina u7100 so please pardon if I do anything stupid. I replaced the u7100 and q7180 just in case they were fried.

Basic voltages:
3.42 present obv

u7100 (no battery)
1. 15.36
2. 16.35
3. 3.9
9. 1.06
12. 3.39
13. 3.26
14. 3.066
15. 0
17. jumps around .500v to .800v or so
19. 5.51 (isnt it supposed to be 5.1?)
20. 5.51
27. jumps between .226 and .336

Resistance 17+18 @ 3.4 // 27+28 @ 21.1

 

[2informaticos]

"9. 1.06"
There is a problem with CHGR_AMON.
"27+28 @ 21.1"
Did you check it directly between chip pins???

Does it start in SMC bypass mode?

 

[down1nit]

Thank you. Is AMON generated by the ISL?

I did indeed check directly between chip pins, unpowered.

It does not seem to start in SMC bypass mode. I keep power button down for 5 sec, plug in, keep holding for another 10 seconds. Current draw is up .01 from .02 to .03 but no other activity.

 

[2informaticos]

CHGR_AMON depends by current flowing through R7120.
If R7120/21/22 and their traces are good, then change U7100.

 

[down1nit]

Changed the U7100 twice more, finally got ppbus. So does the GPU though. I swear I checked every coil to ppbus fuse, maybe missed it. Good riddance honestly, I have another one with the same specs i've been holding on to, can finally sell it.

Thanks 2.