820-3476 IPBR sensor (BMON)

[jadao]

This board had a very small unique spot of water on bottom side near audio chip.
The rest of the board is intact, I replaced keyboard because some keys were not working anymore.

Laptop works perfectly but with EFI I have IPBR over high limit error when only battery.

When battery +charger plugged in I have no errors when I run EFI.

I inspected ISL area with sensing resistors on pins 17-18 (4.6ohms) and 27-28 (20,8ohms) and R5429 300kohms.

IPBR value reported is 1.984A. Normal range should be [0.0-1.5]A.

Except a bad battery I don't see anything else that may cause this error. I went over one complete charging discharging cycle and it holds charge a good 6 hours with full screen video and apps running, nothing heating.

Any advice beside trying antother battery tomorrow?

 

[dukefawks]

I don't see how a battery can cause this. It could of course be that the system is really pulling that much current, but I doubt that as the battery would not last 6 hours.
Could be a bad ISL or crap under the SMC pulling up the BMON line. Crap under SMC is my first suspect.

 

[jadao]

Yes this has nothing to do with battery, tested with another one.

Ok I will give a slight reflow to smc even if board looks immaculate this will eliminate one variable, and replace ISL if no result with reflow.

Didn't had time today for this board, except that I ran again EFI and now it's reading below 1.5A: 1.388A, 1,425A, 1,396A but still gives IPBR error?!?!
How come above high limit error is triggered when it's reading below 1.5A?

 

[jadao]

I gave a slight reflow to smc but nothing changed, and i can assure every single pad is gold on this board, nothing went inside smc. Still IPBR error while hardware profile showing a value within the acceptable range [0 - 1,5]A ...
I replaced ISL6259 just to make sure, but still IPBR error with 1.382A. I am just about leaving it like that except if you have any other idea to explore.
Thanks

 

[dukefawks]

Check if any other sensors are reading higher than they should. It could be that the VREF voltage for the DACs in the SMC is off. This will trow off all analog measurements.

 

[jadao]

No Title

I checked other sensors and they are all in spec as shown in pictures.
IPBR is the only one high but still within the range. Maybe the smc internal converter the one specific for battery monitor?

 

[dukefawks]

I did not ask if they were "in spec" I asked if they actually read the correct value. Good one to check would be PPBUS and VP0R.

 

[jadao]

Oh sorry, you want me to measure power rail and compare it with VP0R reading:
With battery only (fully charged) and EFI 3S162 loaded, I have 12.25V measured with my multimeter on PPBUS_G3H while EFI reads VP0R at 12.232V.

Don't know it it's of interest but I do measure 12.56V with multimeter on PPBUS_G3H when I boot normally into macOs or directly on bare logicboard with only battery.
Thanks

 

[dukefawks]

That all seems fine. If it runs ok then just leave it.