A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

[zpi]

Hey guys, so i have here really strange board...

These steps needs to be done to get a chime board starts to load osx but freezes with no loading bar:

1.Disconnect battery
2.P+R+CMD+OPT to pram reset
3.After only 2-7 atempts to pram reset i get chime.
4.Then i get chime allways, but if i connect battery, then boards stops to chime till i make steps from 1 to 3.

Board looked very clean, no liquid damage. Already replaced isl6259 and SMC, good known battery. Still same problem, sometimes turned off board without battery uses 0.03 amps. Sometimes it uses 0.03 amps for only 2-5 seconds after turned off, sometimes it uses amps till i disconnect magsafe. Turning on with SMC bypass gives same results, with battery max fan and no chime.

Any sugestions?

[piernov]

Re: A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

Tried flashing known good EFI with clean ME?

[zpi]

Re: A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

Tryed fromnanother board, with not clean me, looks same. I will try clean one, as i suspected a bit because osx is not loading, but dont had problems with battery previously when testing boards with not clean me.

[zpi]

Re: A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

Correction:
MacBook will freez only if i try to boot to USB OS, so probably that got corrupted. It boots fine to ssd os, even if i connect battery when os running, it recognizes it and shows percantage, even work from it. But after restart it will not chime no more

[zpi]

Re: A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

Changed another efi chip with clear ME region, still same thing. Maybe somebody knows what exactly happens when pram reset is done? And what it shares with battery ?

EDIT:

Digged up where i can see, that problem is with battery signal smbus_smc_5_g3_sda, because if i remove charging mosfet, board still wont chime if battery connected. But if i only disconnect smbus_smc_5_g3_sda pin on battery connector, boiards works fine, works even from battery, but offcoursethen battery is not recognized. So how good known battery can brick smbus_smc_5_g3_sda line ? And only after pram reset and disconnected battery board starts working

[Weelcup]

Re: A1466 820-00165 Chime and freeze on osc loading, with battery no chime.

I have had same issue with mid 2015 A1398. Basically, i had to pram reset with bateery disconnected of course in order to get chime and then it will literally freeze and fan at max.
I have tried many of bios dumps with ME cleaned but non worked for me. In my case the gpu main rail power was missing due to enabling signal from its controller which was inturn missing a signal from the gpu itself. So i suspected the gpu but never go further.

I am going to check the signal you mentioned, and see if that was the case here too.

Though, when I was searching for an answer online most people who fixed similar issues refered to bios issues. But just like you, i had no luck to fix using any working bioses.

By the way, i had already replaced the smc ICs and the battery charging controller and also heated the pch but no luck. Same issue presist.