820-01041-07 5v on charger

[hambook]

I've got an 820-01041-07 on the bench that pulls 4.89v 35mA. Board is immaculate, no liquid anywhere and all indicators are still white. PPBUS is 3.74v, checked for CHGR_EN_MVR and it is missing. Is there anything else to check before suspecting the ISL9240?

 

[2informaticos]

U7000 is the first suspect.
But should take some diode mode readings and voltages around it.
Check its basic voltages; P_IN, AUX_DET, VDDA/P.

 

[hambook]

Checked those voltages, I get 3.78v on VDDA, 4.68v on VDDP, 4.8v on P_IN, and 1.21v on AUX_DET. Apologies if this is a stupid question, but I've never troubleshooted around this area of the board before, what lines should I check with diode mode and what sort of values am I looking for? I wish I had another working model of this board to compare to.

 

[2informaticos]

"I get 3.78v on VDDA, 4.68v on VDDP"
There is a big difference, change U7000.

Diode mode on PPBUS_G3H and 3V3_G3H are dirst to check, if missing these voltages.

 

[hambook]

Will change U7000. Is it safe to assume that most everything on Aliexpress doesn't have firmware and won't work? Otherwise I'll have to pick up a battery case as a donor.

 

[2informaticos]

Real new ISL9240 is not available; do not trust chinese sellers.
It is Apple proprietary chip, Intersil cannot sale it to anyone else.

Buying removed chips can't assure the quality.
You can try getting 5-10 in the same order; maybe half of them are good.

 

[hambook]

Forgot I had a recycled board with an ISL9240, used that for the swap and I now get 4.95v 0.01a. VDDA and VDDP of the new U7000 are 4.95v, P_IN and AUX_DET are the same.

 

[2informaticos]

What about F7000 voltage now?

 

[hambook]

Hmm, F7000 is 0v now. Diode mode says 0.103 with red probe on ground

 

[hambook]

Sorry, F7000 is actually 0.927v

 

[2informaticos]

Diode mode to ground on both directions?

 

[hambook]

Looks like the same diode mode reading of 0.103 on either side of F7000.

 

[2informaticos]

I said in both DIRECTIONS; red and also balck probe at ground!

 

[hambook]

Sorry about that. Just checked with red as ground and then black as ground, both give 0.103

 

[2informaticos]

Please check in diode mode, not ohm scale...

 

[hambook]

I just measured again and double checked that I am in diode mode. I'm now getting 0.770 with the red probe as ground, and 0.910 with the black probve as ground.

 

[2informaticos]

Now check if you get the same readings in any big coil.

 

[hambook]

No big coils have the same reading

 

[2informaticos]

Remove F7000/1 and check C7050 voltage.

 

[hambook]

Looks like with both F7000/1 removed C7050 is at 12.27v