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820-3330 no ppbus, PPDCIN Fluctuating.

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Ryanlen2

Member
PPDCIN - 16.4 - 16.6V (bounces up and down)
PPBUS - 2.3 - 2.4V
PP3V42 - 3.392V (Green light present)

PPBUS Diode
Pin 2 F7040 .435

U7000
Pin 27/28 20.1 Ohm
Pin 17/18 3.0 Ohm
Pin2 - 16.4 - 16.6 V
Pin 23 - 2.37 -2.39 V


Q7080
16.50 - 16.86 on source
6.42V on gate
R7081 pin 1 - 2.4 - 2.6V

Powered from Bench PSU
Set to 18.5V
When I plug in magsafe amps goes to 0.001 then to 0.0
So, no current.
(green light is always on when attached to PSU)

Thanks. Have a good one.
 
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Ryanlen2

Member
With F7040/41 removed PPBUS is 1.5V to 1.8V (up and down). PPVBAT_G3H_CHGR_REG is 2.1V to 2.7 (up and down). R7020 is 2.6V to 2.8V (up and down) ISL has been replaced already. Battery only 11.43V on PPBUS with fuses back on. This board was obviously damaged by liquid in this area. Also pins 47/48 were a bit burned on U7400, which has been replaced.

* If I took diode measurements on every pin of ISL and compared to working board, would that tell me anything. Or just that the ISL is OK?

Thanks Duke, have a good one.
 
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dukefawks

Administrator
R7020 should have DCIN voltage, so the input FET is not opening. This could be an ISL issue the FET itself or traces/resistors.
Check all voltages to U7000 first, DCIN, VDD, VDDP. Check traces and resistors from AGATE and SGATE to Q7080. Check traces to Q7030/35, possibly replace them if in doubt.

But you could just connect a charged battery, the board should be able to power on from that if it is recognized. See if the battery indicator works, then the board should power on if you short the power pads. You can bridge battery main output to PPBUS and bypass Q7055 and the fuse, providing PPBUS is not shorted of course!
 
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Ryanlen2

Member
Hi, hows it goin? Ok, so got PPBUS working slightly low at 12.25V after replacing ISL along with Q7080 along with surrounding components. Also found damaged trace in the area. PPDCIN is still fluctuating slightly.

Charger Only - 2.25V PPBUS and green light. Fan spins for 1 or 2 rotations then stops.
Battery Only - 12.25V PPBUS . Fan spins 1 or 2 rotations instantly as soon as it is plugged in then stops. No power pads being shorted.
Charger and Battery - 12.25 PPBUS, Fan spins 1 or 2 rotations then stops. Charger stays green. Doesnt recognize the battery.

Reflowed then replaced SMC
SMC_RESET_L - 3.281V
SMC_ADAPTER_EN - 3.365


Thanks man.
 
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dukefawks

Administrator
On the charger you should of course have 12.3 or 12.6V. I still would like to know the voltages I asked and which trace was damaged?
 
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Ryanlen2

Member
Of coarse... Here are the measurements... Sorry.
Yea I know PPBUS is too low.

PPCHGR_DCIN - 16.4 - 16.64V
VDD - 5.49V
VDDP - 5.49V


Actually it was couple traces. Here is pic. Like I said , this section of board got hit pretty bad. It its cologne. Every time I heat it up with hot air the inside of my nose burns. LOL.
Thanks.

https://photos.app.goo.gl/ikgTgfANsoxFtfbL2
 
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Ryanlen2

Member
If your referring to pin 18 to pin 2 to C7050, there is continuity even though it looks awful. I guess I'll run a wire just in case its not sound.
 
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dukefawks

Administrator
It will most likely be a corroded trace from the ISL. Verify every pin of the ISL to the connected resistors/caps/FETs. UGATE/SGATE/LGATE/AGATE/PHASE are the first suspects assuming you checked resistance on pins 17/18, 27/28.
 
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dukefawks

Administrator
BTW, this board should power on from a charged battery if the battery indicator is working and showing a charge. No use in wasting time on the ISL circuit if it doesn't even work from battery.
 
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Ryanlen2

Member
Does Not Work From Battery. Same 12.25v on ppbus 1 fan spin.

** Since last post I changed SMC to rule that out in case last one was bad. Now I have no grn light. Ppbus is still the same whether its battery or charger power. 3.39v on pin 5 u6990. 3v on pin 12 ISL. SMCBCACOK is 2.9v.

Idk... I may end up giving this one back.
 
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Ryanlen2

Member
Hey, good afternoon Duke. No... BIL does not show a charge. But then again I just noticed that pin 10 of J6955 is totally missing and C6951 looks like shit. Which is par for the course for this board as you can see...

https://photos.app.goo.gl/Ov9Vs1LeT4MIOOly2

Do you think I should just throw in the towel on this one, given the way the rest of this board looks?

Thanks man, have a good one.
 
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dukefawks

Administrator
My honest opinion is that this board is way too corroded to make it work reliable. The amount of corrosion before cleaning must have been pretty bad.

Also SMC is probably not running if BIL is not working so this will be a rabbit hole to hell and back.
 
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