A1990 820-01041 5V .4A Troubleshoot

[abajor]

I have the above mentioned MBP, quick scan with thermal camera revealed that only U3200 was heating up. I found that C3208, C3219 and C3205 were all reading ~6.8ohms to ground.
so I swapped U3200.

I connected the PSU again for a quick check on thermal it's drawing about the same amount of current but now I'm seeing only heat radiating from U7800 and the T2 chip from under the black shielding fabric, and the bottom of the board.
It's hard to judge the actual temperature without removing the shielding.

Does anybody have any insights?

PPBUS_G3H is present 12.3V
PP3v3_G3H is present 3.3V
PP3v3_S5 is 1mV
PP1v8_G3S 0v
PP3v3_S5 is reading about 87.7k Ohmr

On the https://logi.wiki/index.php/CD3215_Bootup_Sequence

PP20V_USBC_XB_VBUS is present 5V
PP3V3_UPC_XB_LDO is about 140mV
PP1V8_UPC_XB_LDOA is a few mV

I stopped there since I believe that being absent is an issue in the power up sequence.

[reformatt]

Sounds like T2 isn't running, so make sure it's not in DFU. Also check SSD 2.5V power rails for shorts. Common to have corroded caps on the edges of the board on these models.

CD3215 when swapped need to the same model as the others. Best to swap that from a donor board, plenty of fakes on the market.

[abajor]

I stole the CD3215 Chips from another A1990 so we should be gucci unless they are incompatible between the same models?

[abajor]

Sounds like T2 isn't running, so make sure it's not in DFU. Also check SSD 2.5V power rails for shorts. Common to have corroded caps on the edges of the board on these models.

CD3215 when swapped need to the same model as the others. Best to swap that from a donor board, plenty of fakes on the market.

I'll see if it's DFU now. Can one DFU just the board safely without fans out of the case?

[reformatt]

For T2, use the CD3217 power sequence instead for troubleshooting.

https://logi.wiki/index.php/CD3217_a...er_on_Sequence

Don't focus on 20V negotiation for USB-C, the primary thing to focus on is the T2 power sequence. Rule out DFU first though. A restore wipes the SSD data BTW, so it's often the last resort rather than the first one.

[abajor]

Don't focus on 20V negotiation for USB-C, the primary thing to focus on is the T2 power sequence. Rule out DFU first though. A restore wipes the SSD data BTW, so it's often the last resort rather than the first one.

Right that's what I'm trying to avoid. I know the Apple Configurator will show a giant DFU if it's in DFU mode, can I check with bare board no battery?

[abajor]

For T2, use the CD3217 power sequence instead for troubleshooting.

https://logi.wiki/index.php/CD3217_a...er_on_Sequence

Don't focus on 20V negotiation for USB-C, the primary thing to focus on is the T2 power sequence. Rule out DFU first though. A restore wipes the SSD data BTW, so it's often the last resort rather than the first one.

I tried checking DFU with just the USB connectors mounted to the board, nothing showed up on the apple configurator on my 2015 mbp.

PP1V8_SLPS2RSW_DFR isn't present. The sequence says only PP1V8_SLPS2RSW but my board view only finds with _DFR.

[reformatt]

Power rail names in that sequence are slightly different as they are for later model boards. If you have FlexBV, you can load the sequence from Openboarddata. Alternative is to use the data directly (at least this gives you the correct sequence names):

https://openboarddata.org/?a=generat...pple/820-01041

Is PP1V8_SLPS2R present? This is very early in the sequence and is generated by U7800.

[abajor]

Power rail names in that sequence are slightly different as they are for later model boards. If you have FlexBV, you can load the sequence from Openboarddata. Alternative is to use the data directly (at least this gives you the correct sequence names):

https://openboarddata.org/?a=generat...pple/820-01041

Is PP1V8_SLPS2R present? This is very early in the sequence and is generated by U7800.

Ohh wonderful. I was trying to figure out if there was power sequence data. I'm confused are the openboarddata files separate from the board view and pdf, or normally included in the board view?

[reformatt]

These things are authored and contributed by volunteers in the repair community. Openboarddata is a repository for this data and is run by Paul Daniels (author of FlexBV). Check out the website at https://openboarddata.org/

Since this integrates into FlexBV, you can go through the sequence one by one and it will highlight locations in the boardview, rather than having to search for it. Saves buckets of time. FlexBV is worth the investment if you repair boards regularly (Paul now has a free limited function version if you want to check it out). Its based on OpenBoardView but that does not have this integration AFAIK.

[abajor]

These things are authored and contributed by volunteers in the repair community. Openboarddata is a repository for this data and is run by Paul Daniels (author of FlexBV). Check out the website at https://openboarddata.org/

Since this integrates into FlexBV, you can go through the sequence one by one and it will highlight locations in the boardview, rather than having to search for it. Saves buckets of time. FlexBV is worth the investment if you repair boards regularly (Paul now has a free limited function version if you want to check it out). Its based on OpenBoardView but that does not have this integration AFAIK.

Oh no I have have already purchased it with great zest and gusto. I just didn't know about that feature, so now I must investigate it.

[reformatt]

Load your board in FlexBV, go to Preferences, search string and search server. Use the minimum string (like 820-00165), leave off any -A etc. Openboarddata will appear as diode values on the boardview if present, and you have Notes/Solutions on the RHS with power sequence, USB-C checks etc.

[abajor]

So for the boot sequence everything looks good until I hit PMU_PVDDMAIN_EN which is low, after that P3V3MAIN_PGOOD is low.

I don't know if there is anything else to investigate based off of that.

Also the Board View File doesn't appear to have H9M_24MHz_Clock although I imagine I can check other 24MHz lines?

[reformatt]

PMU_PVDDMAIN_EN should go high after the T2 loads its SPI ROM data. It's basically performs the functions of the older SMC's with extra security features (SSD control/encryption, fingerprint, activation lock etc).

I did have this on one previously, DFU revive didn't work. Customer refused to allow me wipe the SSD data, so I was unable to try DFU restore. I told him it's either a bad T2, needs reballing, or it needs a restore and handed it back.

[abajor]

PMU_PVDDMAIN_EN should go high after the T2 loads its SPI ROM data. It's basically performs the functions of the older SMC's with extra security features (SSD control/encryption, fingerprint, activation lock etc).

I did have this on one previously, DFU revive didn't work. Customer refused to allow me wipe the SSD data, so I was unable to try DFU restore. I told him it's either a bad T2, needs reballing, or it needs a restore and handed it back.

So with the voltages I'm reporting you don't think it's possible I messed up the USB chip swap? Every usb connection now reads the same 5V .4A draw Doesn't show DFU in apple configurator.

U3200 no longer shows shorts or is heating up but I'm also still getting my feet wet with bga swaps.

I do remove as much of the lead free solder as possible then put leaded solder on the board pads and try to watch the surface tension pull the chip into place.

I learned the hard way that I probably shouldn't have solder balls on both sides, that appears to make things bridge prone.

[reformatt]

You have PPBUS_G3H at 12.3V, which means its boosting 5V ok. But this reading indicates the T2 isn't running, which is evident by PMU_PVDDMAIN_EN not being released. Failure to get to 20V isn't because of the CD3215, it's because the T2 isn't progressing further in the sequence. But you can review all the readings in the notes of FlexBV for CD3215 if you want to double check.

Check this thread, fault was resolved with a DFU restore:

https://boards.rossmanngroup.com/thr...k-at-5v.55802/

Also review the wiki thread to check other things prior to doing a restore, if you are wanting to exhaust all things to save the data.

https://repair.wiki/w/MacBook_Pro_A2...w_at_5V_repair

If you turn up nothing after that, it would seem to be an issue with the T2 itself.

[abajor]

I guess one thing I didn't notice is that the voltage was cycling at the fuse.
Another tech looked at the laptop and thinks that this is indicative of SSD failure.

I'm not so sure of that? I did measure voltage at the SSD, but I didn't watch it over much time.

[highpulse]

hey guys , rarely posting here with the tons of work on the lab , doesn't give me much time to come here ofter as i should to contribute a bit , anyway crossed to this thread by searching some info on this model board 820-01041. i have a tip that might make people waste time for nothing and resources , something that i can't afford on this moment due to the huge ammount of work i have , as most of you know makor parts of usbc ics depending on board model , work as pair or single , in the case of this board , if for ex U3100 is missing PP1V1_UPC_XA_LDO_BMC if the C3104 cap is ok , don't bother in replacing the u3100 usb ic (altough make sure your with the charger on the currect port to make sure this LDO line is ON , otherwise it wont show up . anyway if your charge is on the port for the u3100 and PP1V1_UPC_XA_LDO_BMC is not working then the issue is not the u3100 but u3200 (EVEN IF WHEN TRYING THE CHARGER ON THIS PORT ALL LDO'S ARE OK ) i got tons of this model and 1 in 50 perhaps was not the issue i mentioned , so this info might save you time and resources .

take care and good repairs for all