820-2850 not turning on

ytesfay80

Member
Okay with only charger plugged in PPBUS_G3H pulses and is not stable from anywhere around 3v- 12v
With the battery plugged in and charger plugged in it pulses from around 12.1v to 12.5v
With the battery only it is at a stable 12.1v.
 

ytesfay80

Member
When you say check all coils for shorts which coils are you referring to?

The fuse 0v in diode mode so I believe it is fine. L7030 did not measure as a short.

I removed F7040 and checked ppbus_g3h again and this is what I got.
Pin 1 - still pulses from 12.57 not stable.
Pin 2(PPBUS_G3H) - 0.56v and slowly goes down.

(Measurements with F7040 removed from the board)
I went and checked the current sensing on u7000 they all measured fine. I got 5v on VDD but on Pin 3(ACIN) I was getting 0v.
D7005 is pulsing between 16.3v - 16.83v. Pin 1 of R7010 also had the 16v but Pin 2 shows 0v.
In resistance mode R7010 measured 30kohms but r7011 measured only 2ohms.


While taking those measurements I noticed the charger light is now dim green and doesn't turn bright green anymore when I plug the charger. Tested with another Dcin board and same issue.
PP3v42_G3H is 3.41 while SMC_BC_ACOK is 0v.
 
Last edited:

dukefawks

Administrator
I don't know what you are doing but now it seems you killed the 6259.....
Also according to the diagram there are 2 fuses 7040 and 7041, no idea if they are on the board too.
 

ytesfay80

Member
There is no f7041 on the board.
I put F7040 back on the board and replaced the isl6259 and the green light came back on and SMC_BC_ACOK is 3.1v and CHGR_ACIN is back at 3.9v
PPBUS_G3H is still at only giving me around 1.08v
 

dukefawks

Administrator
Well, remove F7040 and check again. This time don't kill the 6259...
If it still is not stable at 12.xx volts then check the sense resistors and traces.
 

ytesfay80

Member
Some more crap happened. I removed F7040 and measured Pin 1 of F7040 and it was stable around 6v. Pin 2 had around 0.3v. I unplugged the charger and plugged in back in about 10 seconds later and now I have no light on the charger at all. I didn't take any measurements other than on the pads of F7040 so I don't think I killed anything.
F6905 is pulsing and only goes up to 0.23v.

I measured the current sensing on U7000. Pins 27/28 - 20.5ohms Pins 17/18 - 3.1ohms
The traces are good when I measured in continuity mode.

I've tried putting F7040 back on but still no change and I tested with another Dc-in board and the same thing happens.

Is this issue worth continuing to troubleshoot it?
 

ytesfay80

Member
I don't think its the charger. I plugged the charger into my 2011 MBA and the light came on the charger and it was working.
Its not the Dc-in board because I plugged the same one into a 2012 MBP and it had a light on the charger.

When I plug it back into the 820-2850 there is no light on the charger at all.
 
Last edited:

ytesfay80

Member
I get 0v on all of those. The only voltage I get is on PPDCIN_G3H. It pulses every few seconds and only goes up to 0.25v

When I measure in diode mode on pin 1 of R7010 I just get OL.
 

dukefawks

Administrator
Something wrong in 6259 circuit. Do you have a fake chinese charger to check, it will not shut down like an Apple one.
 

ytesfay80

Member
Ok. The fake charger lights up. SMC_RESET_L and pp3v42_g3h are both high. SMC_BC_ACOK is 3.26v and ppbus_g3h is around 0.09v (F7040 is still removed from the board)
Pins 27/28 of U7000 - 20.7ohms - Pins 17/18 - 3.1ohms
 
Last edited:

ytesfay80

Member
No short on ppbus_g3h. In diode mode I get 0.49 on Pin 1 of F7040(PPBUS_G3H).
Could this be an issue with the isl6259? Should I try putting a new ISL on there?
 
Last edited:

ytesfay80

Member
I think I might just send this machine back.
I replaced the ISL6259 and the green light came on I was able to see PPBUS_G3H was pulsing from 12.56 to 4v on Pin 1 of F7040. I also took some other measurements.
U7000
Pin 13(CHGR_RST_L) - 3.36v
Pin 3(CHGR_ACIN) - 4v
Pin 2(CHGR_DCIN) - Pulses from 16.2v to 15.7v

Then minutes later the green light went away as if the isl died again. I replaced with another 6259 and that had a dim green light until about 20 minutes later I plugged the charger in and the light turned green again. The light went away and I replaced the 6259 again and now it is again giving me a dim green light and 0v on SMC_BC_ACOK.
I don't know what keeps killing the ISL6259. All of the sense resistors and the traces are fine.
 
Last edited:
Top