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820-01598 HELP.

T

tech-fix

New member
Hi.

i have a macbook pro here that had liquid damage on the EDC180 area. checked ic and was shorted. replaced it with one from mouser and now i have 3.3v again ( with R3964 AND R3965 REMOVED) with these resistors in place the voltage is low. pulsing around 200-300ma when connected to a meter via USB-C.

checking from those resistors to ground im getting 1.3 ohms. also when checking PPBUS-G3H im only getting around 7v. pretty sure i have a short somewhere but unable to locate it even with a thermal camera.

the 1.3 ohms is in regards to PP3V3_G3H_RTC. Is this a correct resistance reading for this line?

Please save me from pulling anymore hair out.

thanks
 
2informaticos

2informaticos

Administrator
Staff member
I suppose you've meant R6934/35 instead.

1.3 ohm is low enough to use voltage injection method.
Start with 1V and slowly increase, if needed; no more than 4V.
Set first amp limit on lab PSU to max.
 
T

tech-fix

New member
2informaticos said:
I suppose you've meant R6934/35 instead.

1.3 ohm is low enough to use voltage injection method.
Start with 1V and slowly increase, if needed; no more than 4V.
Set first amp limit on lab PSU to max.
Click to expand...
Hi thanks for the reply.


yes you are correct regarding the resistors.

i did this and could not locate the issue. however i have found a shorted U8250 on the PP3V3_G3H. Removed it and tested both incoming and outgoing on the board and short is now gone. However i do not have a spare U8250 anywhere. The part number according to schematic is SLGAP1569V/SLG5AP1569 depending on what part you read, searching this brings up nothing on google apart from aliexpress etc. however i can find a slg59m1558v which looks to be the exact same part.
are you able to clarify this?

thanks
 
T

tech-fix

New member
2informaticos said:
Compare schematics which use both chips.
If they have the same size and pin layout, should work.
Click to expand...
unfortunately the schematic for the one apple use is non existent. however they do list specs on their schematic which does mary up with the ones from mouser.
 
2informaticos

2informaticos

Administrator
Staff member
You can try a bypass, just for test.
Power on sequence timings will be affected, we don't know how PCH and T2 (SMC) will react.

Don't quote an entire post visible few centimeters above.
Write in the reply box, instead of clicking Reply button.
Please, maintain forum aesthetic...
 
T

tech-fix

New member
ok no problem.

so short removed from pp3v3_g3h, however my 1.3 ohms on the pp3v3_g3h_rtc is still there. connecting my psu up to it again @3v 2amps shows a heat signature coming from U2800. However it is faint given that is under a shield. Im a bit puzzled as when checking the RTC 3.3v line on the board view nothing goes directly to that area.

thanks
 
T

tech-fix

New member
a bit more digging shows that pin 3-4 on U8290 where shorted. now i still have 1.3 ohms on PP3V3_S0_TBT_X_ISNS_R but unsure if this is normal or not.
 
T

tech-fix

New member
ok i did this and short has gone. i have replaced u2800 with one from mouser and now its worse, im now getting 5v and 10ma on charger with and without battery. getting nothing out of 3v3_rtc where i was before. loosing the will to live with this thing
 
T

tech-fix

New member
unfortunately i dont have one. i ordered 2 from mouser. both the same. however i think the issue is my using a little to much heat and the board has warped slightly. So annoyed with myself
 
T

tech-fix

New member
pretty sure this is 2019 model. like i said with usb-c it doesnt charge or do anything. just sits at 5v 5-10ma. only way to charge the battery will be either via another macbook the same (dont have one)or charging it from my DCPS which im used to doing.
 
2informaticos

2informaticos

Administrator
Staff member
I didn't expect to charge the battery.
If stays at 5V with charger alone, test if is recognized in DFU mode.
 
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