820-2915-A Wont power on with battery connected

[beogeek]

Re: 820-2915-A Wont power on with battery connected

I'll report back once I get my hands on a replacement, I'm hoping it's the battery as this puzzle as you call it was definitely dialed up to 11 on the difficulty scale!

[macattack600]

Re: 820-2915-A Wont power on with battery connected

Order Apple original make sure your using original OEM Battery and Charger before you dig deep!

Knock off cause alot of problems. In system profiler it identifies chargers and batteries , the chips are proprietary made in them.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Order Apple original make sure your using original OEM Battery and Charger before you dig deep!

Knock off cause a ton of problems in system profiler it identifies chargers and batteries , the chips are proprietary made in them.

Yes, I'm aware of that, the problem is finding an original, even the local authorized apple shop doesn't have them nor will it as according to them apple has discontinued support for these models so they no longer stock or manufacture these batteries...

[mon2]

Re: 820-2915-A Wont power on with battery connected

See attached. Confirm the highlighted set of components.

This is for the PPVBAT_G3H_CHGR_R.

Measure the voltage @ CHGR_CSO_R_N (R7050, pin # 1&3).

Measure the voltage @ CHGR_CSO_R_P (R7050, pin # 2&4).

Then confirm the linked parts are as per the schematic. Check the resistance of the resistors.

What is the voltage

@ R7051, pin # 1 ? (with battery)
@ R7052, pin # 1 ? (with battery)

[beogeek]

Re: 820-2915-A Wont power on with battery connected

All readings are done with bat only.
R7050 12.26v on all 1-4, resistance 0.02Ω
R7051, pin # 1 - 11.73v
R7052, pin # 1 - 12.26v

The highlighted area around U7000 is all within specs, all remaining resistors around U7000 are within the spec also.

[mon2]

Re: 820-2915-A Wont power on with battery connected

R7050 12.26v on all 1-4, resistance 0.02Ω
R7051, pin # 1 - 11.73v
R7052, pin # 1 - 12.26v

The voltage on R7051 does not look correct.

Can you confirm the voltage @ R7051, pin # 2 ? It should match the voltage present on the current sense resistor = 12v26.

Respectively, then remove all power, meter in the lowest resistance mode.

Confirm the resistance of R7051.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

R7051, pin # 2 11.75V

Tested with a Fluke 117 and a PeakMeter PM8236, Fluke 2.4Ω and peakmeter 2.3Ω

[mon2]

Re: 820-2915-A Wont power on with battery connected

Very strange.

See attached. Is my understanding correct ?

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Very strange.

See attached. Is my understanding correct ?

Yes exactly, you're understanding is on par!

[mon2]

Re: 820-2915-A Wont power on with battery connected

There is a 0v5 drop on a 'perfect conductor' (trace).

Meter in resistance mode. Check the resistance from R7051, pin #2 and the current sense resistor (pins 2&4). It should be 0 ohms or very close to this value.

If not, use a piece of wire to guarantee there is a solid connection between these 2 points.

Summary: You should not have a 0v5 drop @ pin # 2 of R7051.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

R7051, pin #2 to R7050 (pins 2&4) = 8.22MΩ WTF! I tested with both meters and both report the same thing!

[mon2]

Re: 820-2915-A Wont power on with battery connected

Ok. This could be the root cause of your problems.

Jumper it with a solid wire - wirewrap wire is always good but I am dating myself .

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Ok. This could be the root cause of your problems.

Jumper it with a solid wire - wirewrap wire is always good but I am dating myself .

MON2 I could kiss you on the god damn mouth mate!!

I'm going to re-assemble it in a minute and see if the OS detects the battery!!!

[beogeek]

Re: 820-2915-A Wont power on with battery connected

If anyone comes across this mega-thread, this is what was replaced in order for it to turn on with the battery connected.

U4900 (SMC) U7000 (ISL6259HRTZ), R7051, U5421, U5420, Q7055, D6990!

Just want to openly say I doubt I would have noticed that the resistance from R7051, pin #2 to R7050 (pins 2&4) we're 8.22MΩ instead of close to 0! After spending so much time on this I was just going in circles! All the praise goes to mon2, without your input and help and most importantly patience this would have done my head in for a long while!!! Thank you mon2 for all your help.

It's now charging, running off of battery, and running with battery and adapter connected!!! Bloody brilliant!!!!!!

[mon2]

Re: 820-2915-A Wont power on with battery connected

Excellent! Well done. We all learned in the process and hope it will help future readers. TBH - we should have clued in on the R7051 which you replaced in your first post. Hindsight is always 20-20 but the fact that this part was defective made that entire leg a suspect.

When the world is calm and covid is nuked, not humanity, we will do a road trip and pick up SMDFlea from England, Piernov from France and come to visit you and party like it is 1999!! You have been warned

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Yes R7051 was replaced, in fact, it was one of the first things I noticed that needed replacing. I tested the replacement on the board and out and it was in spec, so that is what took me on a wild goose ride as I assumed it was fine! I can't believe it was the trace that was the issue all along (if we're not counting the SMC, ISL, diodes etc)!!! You know what they say, two brains are better than one, in this case, only one was needed and it was yours, so hats off to you!!! I was just the surrogate surgeon!

As for the party, let's do 1998, 1999 kind of sucked for this region hahaha. If you ever do plonk on by, do say hello, beers, and local foods on me!