MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powered

[reformatt]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

CHGR_ACOK is open drain output so is being pulled low by the ISL because of the bad input to pin 2. It is irrelevant till you sort that out. You may have introduced other issues though from component replacements.

[duwane]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

CHGR_ACOK is open drain output so is being pulled low by the ISL because of the bad input to pin 2. It is irrelevant till you sort that out. You may have introduced other issues though from component replacements.

Thanks for your help @reformatt. I replaced R7005 with a 20 ohm, and I got fan spin, and green light on charger

[duwane]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

The joy was a bit short lived lol. After putting it into a chassis, theres no chime at power on, no display, and fan spins at full speed. Joy lol

[mon2]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

https://boards.rossmanngroup.com/thr...o-chime.58384/

[reformatt]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

You previously mentioned broken pin on RAM slot and you've also replaced the SMC. Are you sure the SMC you used is any good? Maybe reball the old one and put it back on. Review and triple check all your other work before proceeding further.

With the RAM, it should however boot on the one slot that is ok though (would beep at you otherwise). Maybe try known working Clean ME BIOS on U6100. Boards for this model are pretty cheap though if you want to toss it onto the donor pile.

[duwane]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

You previously mentioned broken pin on RAM slot and you've also replaced the SMC. Are you sure the SMC you used is any good? Maybe reball the old one and put it back on. Review and triple check all your other work before proceeding further.

I haven't replaced the SMC. I reballed the one that was on the board. I could try to change it, but I don't have any donor board at this stage. I will recehck my other work as well just in case, and going to check all of the power rails again to make sure there isn't still another issue.

With the RAM, it should however boot on the one slot that is ok though (would beep at you otherwise).

Yeah thats what I was hoping to do. If I managed to fix the board, I would just use the one remaining slot, but the board doesn't even beep with no RAM at this stage.

Maybe try known working Clean ME BIOS on U6100. Boards for this model are pretty cheap though if you want to toss it onto the donor pile.

What programmer do you recommend? I don't have one at this stage, and been wanting to get one but not sure what to get. Also is there a repository of known good BIOS files for each model somewhere, or is it a Google adventure each time?

[duwane]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

https://boards.rossmanngroup.com/thr...o-chime.58384/

Thanks @mon2. See my response to reformatt. I don't have a programmer, but going to try that and a possible SMC swap if I can find a cheap doinor board. (Anywhere you know of other than AliExpress lol?)

[reformatt]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

My regular programmer is a SVOD3 but it's a bit expensive if you aren't doing EC programming. I also have a T56 for some of the other stuff, but the interface is a bit convoluted compared to the SVOD. RT809F comes highly recommended by others but I haven't used it.

If you are looking for donors, use eBay for either faulty units or boards. Aliexpress boards are usually raped for anything useful. SMC's off these boards are normally corroded/delaminated. Only good for passive components or connectors really.

[duwane]

Re: MacBook Pro A1278 - No charger light, no PPBUS_G3H, SMC_BC_ACOK short when powere

My regular programmer is a SVOD3 but it's a bit expensive if you aren't doing EC programming. I also have a T56 for some of the other stuff, but the interface is a bit convoluted compared to the SVOD. RT809F comes highly recommended by others but I haven't used it.

If you are looking for donors, use eBay for either faulty units or boards. Aliexpress boards are usually raped for anything useful. SMC's off these boards are normally corroded/delaminated. Only good for passive components or connectors really.

Thanks for the info. Will check out some of those models and see what will work for me. For now I have purchased a CH341A USB programmer and SOIC in circuit clamp, along with a WSON/USON adapter which looks like it should work as a temporary measure. Only a few dollars, so not a huge loss if it doesn't work well.

RE donor boards: yes learned my lesson with AliExpress donors lol. As you say, most good stuff is raped from board, and the rest are overheated, and normally all smeared to one side of the board, so not very useful.