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A1534 charging issues (820-00244)

ALB-Repairs

ALB-Repairs

Member
Got an 820-00244 a1534 here, Managed to get it to run by restoring pp1v8_SUS, did a backlight repair too.

But it only runs on the battery, D6900 does not illiminate untill SYS_DET is jumped, PP3v3_G3H is not present
PPDCIN_G3H is not present, Q3100 is not shooting it out.

my understanding of these is poor so i am trying to familiarise myself. F3050 is good and the voltage is present there. The USB-C port/cable is new.
Am i correct in thinking U3100 is that uses the power_gate_enable line to gate q3100? following that would lead me to PP3V3R3V0_AON

PP3V3R3V0_AON Is not present when just the charger is plugged in.
My other concern is that i am missing pp1v2_S5SW completely.

(not present when on battery or with the charger plugged in.)
 
ALB-Repairs

ALB-Repairs

Member
Apologies, forgot to state i get 15V on PPVBUS_LIO. it just doesnt get gated past Q3100 (unless q3100 is bad, rather than it missing gate signals, which i doubt)
 
D

dukefawks

Administrator
The charger needs to communicate with the system to set it to 15V so it is working mostly.
What exactly happened to 1V8_SUS?
 
ALB-Repairs

ALB-Repairs

Member
Im not 100% sure, was missing a resistor that i think i removed and then forgot about. Was liquid damaged and a resistor failed, the other was unchecked and i just removed it because it was corroded garbage right near the liquid damage spot.
 
ALB-Repairs

ALB-Repairs

Member
Its impossible to measure Q3100 in circuit. No space around the IC at all :(

it would be risky to pbypass the q3100 (inrush protection) wouldn't it?

With Q3100 removed UPC_XA_GATE2 is 14.9v
UPC_XA_GATE1 is 1.7V
 
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ALB-Repairs

ALB-Repairs

Member
Decided to bypass Q3100 as the inrush protection.
Still not producing PPBUS_G3H
ACIN resistors pulled off and checked good.

PP3v3_G3H is still measuring 0 as well.
 
ALB-Repairs

ALB-Repairs

Member
The heat from resoldering the ACIN resistors seems to have changed the symtoms a bit.

PPBUS_G3H is now 3.7V and PP3v3_G3H has come up to 2.8v or so. Its still telling me its not plugged in. With the battery connected i can see ppBUS_G3H slowly rising from 6.90V
it is currently now at 6.95V so it seems to be charging the battery.

It will not run of the charger alone though, This is all a really weird change in symtom considering all i did was pull and test two resistors. Q3100 is still bypassed, May re-fit it and see if there is any more change.
 
ALB-Repairs

ALB-Repairs

Member
Maybe the resistance of flux in such a densely populated part of the PCB. Had that issue on an alienware SIO chip once. Only ever came back to life after an ultrasonic clean. Im using Amtech 4300 (i find as its water soluble it cleans better)

Anyhow, i cant seem to measure things around the PMIC without slipping and buggering the PMIC so i have to order some PMIC's from china before i can report back- If im lucky it may even fix it.
I also have an 820-0045 a1534 board with a shorted PMIC that had simalar issues (not recognising USB C and not charging but running off the battery) So with any luck ill be able to get that one going as well :).

Horrible little chips to pull and site clean though.

EDITL removed PMIC, shorts not gone, injected voltage. Dead SMC. As far as i know there are no parts boards for the a1534 yet?
 
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