820-2915-A Wont power on with battery connected

[beogeek]

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

Confirming that it doesn't boot off of the battery and adapter with the battery connected, ONLY with adapter and no battery connected. I'm guessing bat replacement is in order.

[mon2]

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

Hmm. That is interesting.

Lift up one leg of L7030 so that U7000 and related parts are out of the equation.

Now ONLY the battery will be powering the logic board.

The voltage from the battery should flow through Q7055 onto PPBUS_G3H.

Test again (with L7030 leg lifted).

If this still does not allow for the logic board to boot normally with only the battery, just wait to test again with a fresh (known good battery).

[beogeek]

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

Does it matter which leg?

[mon2]

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

No - either side is ok. This will just remove the link to U7000.

[beogeek]

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

Removing one of the legs from L7030 yields the same results as before

[mon2]

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

Ok. Wait for the new battery.

[beogeek]

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

Will do, prob Monday I'll pick it up and retest again, I'll let you know how it goes, fingers crossed its the bloody battery!

[beogeek]

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

Sorry mon2, first the supplier delivered the wrong battery! Then I physically went and drove an hour away to return the wrong one and pick up the correct one, returned home and you wouldn't believe it but they sold me a dead battery 0.00V, won't charge, won't even react to charging via the DC lab power supply. SO now I'm ordering again but from a different store...

[beogeek]

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

Ok. Wait for the new battery.

I swear I'm in some kind of reality show, after getting 2x wrong/dead batteries I ordered it from another supplier, and I get sent an A1321 battery... Sure it's for MacBook A1286 but only for Mid 2009, Early/Late 2010...! So now I have to wait again for them to refund me or send the correct god damn battery!

On a side note @mon2, I discharged the old battery and connected it with the MagSafe, it does charge and the orange light is coming on, but it won't turn on with the battery connected as before.

[mon2]

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

1) What is the voltage on the battery after the charge ?

2) If you allow for the battery to charge, does the orange light eventually shut off to indicate a full charge has been reached ?

3) Once you connect the battery but NO adapter, what is the voltage of PPBUS_G3H ?

[beogeek]

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

1) What is the voltage on the battery after the charge ? 12.27v

2) If you allow for the battery to charge, does the orange light eventually shut off to indicate a full charge has been reached ? yes

3) Once you connect the battery but NO adapter, what is the voltage of PPBUS_G3H ? 12.27v

[beogeek]

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

Also what is interesting is that the battery is rated at 10.95v 73Wh but while disconnected measures 12.27v which is after fully charging it and waiting for the orange light to turn green.

[mon2]

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

Is this the original battery from this macbook ? Suspecting that the battery is just spent and unable to deliver the current required to keep this logic board running or that the SMBUS (I2C) interface from the battery pack itself is not functioning.

The logic board may be shutting off if it is unable to communicate with the BMS board inside the battery pack.

[beogeek]

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

No, it's not the original according to the owner, he has had it replaced 3 times because the service that replaced it thought it was just a bad series of batteries, but they didn't know that U7000 was shot and so was the SMC! According to the owner, the batter is not older than a year or so. But when he received it back it never charged or ran off of the battery so he had it unplugged most of that time. It is charging though, and keeping a charge. But as you say even if the cells are fine it may be the BMS inside can't communicate. I guess I'll just be patient for now while I wait for the third damn battery to be delivered.

[mon2]

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

What is the voltage of SYS_DETECT_L ? (with the battery only connected)

Measure again the voltage on D6950:

SMBUS_SMC_BSA_SCL
SMBUS_SMC_BSA_SDA

A good tool to have for such cases is a low cost bus analyzer for I2C / SMBUS investigations. You can pick one up for under $20 USD on Aliexpress.

Then use it to monitor the SDA & SCL lines to review the bus traffic between the SMC and the battery, for your case.

With the tool, it should be possible to see the traffic that is communicating with the BMS and the response.

I recall another thread here where a tech used the Arduino to do the same - was also for the battery review.

update - something like this:

https://github.com/Ri5ux/Smart-Battery-SMBUS-Analyzer


Ok, using my Google-fu belt from Bolo Yeung, found it...

https://www.badcaps.net/forum/showth...hlight=arduino

Have a look at the juicy tidbits that can be reviewed with such tools.

[beogeek]

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

What is the voltage of SYS_DETECT_L ? (with the battery only connected) 0v

Measure again the voltage on D6950:

SMBUS_SMC_BSA_SCL 3.463
SMBUS_SMC_BSA_SDA 3.463

Another idea I had was hacking the replacement A1321 battery, it's the same, only difference is that the + and - are switched, the SMBUS_SMC_BSA_SCL, SMBUS_SMC_BSA_SDA and SYS_DETECT_L is the same pinouts on both...

[mon2]

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

We just don't know what the actual data is supposed to be on a valid BMS for your model. That could be the next show stopper if you swap with another model of a battery pack.

From all indicators, this battery should work since it is charged so believing the fault is now with the BMS.

I think your SMC may still have a fault - see here:

https://logi.wiki/index.php/PPBus_G3H

Can you confirm the value of PPBUS_G3H with only the adapter ?

Is it 12v2 or 12v6 ?

The SAME 2 lines (SCL & SDA) that are dialing up the higher voltage of 12v6 with U7000 are linked to the battery pack communication.

What if, the SMC chip's balls are not soldered onto this interface rail..then U7000 cannot be bumped up to the 12v6 and also will not be able to see the battery pack.

[beogeek]

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

PPBUS_G3H with only the adapter 12.57v
PPBUS_G3H with only the battery 12.26v
PPBUS_G3H with battery and adapter 12.57v

[beogeek]

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

Well as I don't have another donor for this, I'll assume it's the battery and will wait for the replacement to arrive. If the same issue is present then I can do a quick reflow of the SMC or I'll source another A1286 donor board and yank the SMC off of that and replace it again.

[mon2]

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

Since you are at 12v6, the SMC must be working to dial up the voltage on u7000 using this interface.

Can only conclude at this time that that battery pack sms is the quirky one in this puzzle.