A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

[duwane]

Hi All.

I have an A2251 820-01949 board that has come to me for data recovery. Previous repair shop that worked on the board have removed the PMU as they said that the chip had a hole burned into it. I have replaced a bad cap that was causing a short on PP3V3_G3H_PMU_VDDMAIN to ground that I am 99% sure is what caused the PMU to blow. Now I am trying to find a replacement PMU chip U7800 (labled as "CALPE-PMU" in the schematic).

I have several questions about the PMU chip itself:

1) Does anyone know if these chips are identical between boards of the same model, or do they have any board specific data on them? Can I harvest one from a donor board as a direct replacement?

If the PMU chips can be swapped between boards:

2) Does anyone know if chips with the same name in the schematics can be used as a direct replacement from different models? The A2141 board 820-01700 for example has a PMU chip with the same chip name "CALPE-PMU" (U3900 on the 820-01700 board) as the A2551's U7800.

3) Does anyone know of any other models that use the same PMU chips "CALPE-PMU" that I may also be able to harvest one of these chips from?

4) Does anyone know where I can get a replacement PMU chip from? I am not able to find any of those chips for sale on AliExpress other than on boards, and seems crazy to purchase an entire donor board for hundreds of dollars if I just need the 1 IC. Does anyone have a PMU IC they could sell me?

Any help with this appreciated, and thanks in advance to anyone that is able to help with any info.

[mon2]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

Try this (confirmed to be a legit and quality vendor from other readings):

https://www.ebay.com/str/seeic

He may have access to reballed devices. Update this thread for future readers.

You can also try:

Ala Zhang(sales)
****************************************
Shenzhen Exin Era Trade Co., Ltd.
APPLE IMAC MACBOOK MAC MINI IPHONE IPOD IPAD PARTS EXPERTS
“A Goal without a Plan is just A wish”
E-mail: sales05[at]szexinera.com
Tel :+86 18826478312(whatsapp, wechat )
Skype: Exin.ala zhang
Webite: www.ipartsleader.com
Rm122012/F,Bld A,Stars Plaza,Huaqiang North,Futian,Shenzhen,China.
Post code: 518131

[duwane]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

Try this (confirmed to be a legit and quality vendor from other readings):

https://www.ebay.com/str/seeic

He may have access to reballed devices. Update this thread for future readers.

You can also try:

Thanks Mon. I will try both of those and feed back in this thread.

[dellxps15]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

hi all were u able to get CALPE-PMU replacement ? do we need to take it from donor board ?

edit: looks like it's 338S00267 available on aliexpress

[guruji]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

hey
i have the similar model a2251 with the pmic blow.I replaced it and the machine started but macos boots and i login in and it hangs. and restarts again,this loop goes on. But when you go in safe mode everything seems to be fine the touch bar wifi all work but the machine is a little sluggish.
My question is , is this pmic programmable 338S00267-a0,I have tried to do recovery cmd option + R same thing happens it install but when comes to the page for user account restarts.can it be the T2 rom corrupted.

[mon2]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

Review and try the procedure noted here:

By Gurpreet

https://www.ifixit.com/Answers/View/...during+startup

It may also help in your case.

[guruji]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

okay just noticed sometime i disconnected the battery now it all works.no hanging works normal except the fans are running faster.Probably bad battery.

[mon2]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

Confirm the voltage to ground of the SMBUS interface lines on the battery which may be shared with the sensor lines. If strapped, the fans will run at high speed due to incorrect readings from the sensors.

Often ESD diodes on the battery connector region get zapped.

[dellxps15]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

today i got the new ic. after desolder the old one (yes next time i remove it before order new replacement) i see short on l7817 and l78126. i injected 0,8 volt and t2 chip start to get warm. 4A and 0.8 volt power consumption with lab psu.
replace the t2 chip would cost too much and owner wont spent much money on it.

ecity: difference from t2 chip 1g vs 2g ? 2g costs almost double the price....

[piernov]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

T2 2 GiB RAM for SSD>=1 TB

[guruji]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

further i changed the battery same issue.I also changed the pmic again thinking that is bad. But this is soo stranged in safe mode the laptop works fine all devices work well wifi touchbar everything. it has to do something with the T2 rom.I put a blank T2 rom and went in dfu in apple configurator it updated /restore the the machine but the same thing happens.is there a virgin rom repository file i can use.

[ugamazing]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

Make sure it's not a simple damaged battery cable. They can crack if bent/creased by accident. Would match your symptoms. This doesn't sound like a T2 ROM issue at all, in my opinion.

Sounds weird also, but make sure your keyboard cable and the top-case-side connector are OK.

[guruji]

Re: A2251 (820-01949 board) PMU IC U7800 CALPE-PMU

I have checked the battery cable all good as the battery charges well.generally this happens when some sensor is not reporting as the fans are too fast and cpu is really too hot without any process.I downgraded to Bigsur worked for 15mins without safe boot and again back to the same boot and shutdown.is there a way to disable the gpu.