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820-00138: Battery drain when in sleep

M

macRepairAmb

Member
Have this MacBook pro that runs without issues. But once you closed the lid (system goes to sleep, fan is off) and leave it closed overnight, by mid-day the next day, the battery is fully drained. Once, I check it when the lid was closed for a couple of hours and the boards was warm (fan wasn't running). No sure where to start from on this one as there are no corrosion on this board, board looks very clean. I'm about to order a usb-c to MagSafe 2 cable so that I connect it to my usb-c power meter monitor to see if the board is still pulling a lot current when it's off or when in sleep mode. But until i get that part, any suggestions on things to check?
 
M

macRepairAmb

Member
Sorry for the late response

PM_SLP_S4_L - Remains at 3.3v after the system goes to sleep and the fan shuts off
PM_SLP_S3_L - Drops to 0 from 3.3v once the system goes to sleep and the fan shuts off
 
2informaticos

2informaticos

Administrator
Staff member
Looks good.
But machine must go to S5 state after some time, saving cache to SSD (maybe 30 min or so).
PM_SLP_S4_L should drop to 0V then.
Check in System preferences if such option is available.
Or try another macOS installation.
 
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2informaticos

2informaticos

Administrator
Staff member
Try another known good battery.
The board is still hot after 2 hours?
Check how much the battery is drained after 1 hour.
I'm talking about sleep mode, of course.
With a good multimeter, monitor the voltage across R7150, with only battery connected.
You can get the current dividing that voltage by resistor value.
Check if drops under 10mA in off state (battery alone).
Compare value with a good board.
 
M

macRepairAmb

Member
One other thing, if there's still life in the battery, and i allow the computer to sleep for a few hours, when i wake it up, the board comes on with the fan spinning and it starts to ramp up until full spin, the display however never comes up.

Going to get you the above reading shortly.
 
M

macRepairAmb

Member
Also, after about a 3 plus hours the battery only dropped about 2%. Plus this time around the board wasn't warm, but it did have the symptoms mentioned above with only the fan running, requiring me to reboot the system.

Current across R7150 is 49mA. This after the system has been in sleep for about an hour.
 
2informaticos

2informaticos

Administrator
Staff member
There could be a problem caused by FDMF6808 chips.
Some scripts available on Internet, to disable CPU sleep states.
Try that to discard this problem.
 
M

macRepairAmb

Member
Ok. Will replace that. Also, this morning i checked on it and the cpu is now warm with current across R7150 now at 1.534A and the battery now at 27%. I'll let you know how it goes after FDMF6808 replacement.
 
M

macRepairAmb

Member
So online it says to replace the FDMF6808 with FDMF6708, unfortunately i can't find any locally, will just replacing Phase 1 with a new FDMF6808 suffice for now. Also should i replace all 3 phases
 
P

piernov

Moderator
Staff member
There are no new FDMF6808N, and taking them from donor boards isn't a good idea since they can develop the same problem. You can backorder FDMF6708N from Mouser. They're EOL though, not sure what will happen after the next shipment. FDMF3030 could be a suitable replacement but I don't think anyone tried it yet.
 
2informaticos

2informaticos

Administrator
Staff member
FDMF6808N was never sold to anybody else than Apple.
All "new" chips on the market are fake, removed from boards.
 
2informaticos

2informaticos

Administrator
Staff member
"when i wake it up, the board comes on with the fan spinning and it starts to ramp up until full spin, the display however never comes up."
Same thing happens???
 
M

macRepairAmb

Member
yep. Display doesn't come on but the fan turns on. It kinda looks like the fails we see with the A1398 boards that have the separate GPU where the GPUvcore chip U8900 goes bad, except this model doesn't have this or does it something similar to it?
 
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