kjchatman1
Member
this board was shorted at ppbus because of ug800. i've replaced ug800 and still no 20v. what's the function of UG800? is pp5v_s2sw_usbc23 important?
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820-02098 stuck on 5v and no boot
- Thread starter kjchatman1
- Start date
This voltage powers on external devices connected to ports 2 & 3.
Is the machine recognized into DFU?
Is the machine recognized into DFU?
kjchatman1
Member
it will not enter dfu mode. the amber indicator on the magsafe turns off for a second whenever the power button is pressed
Which basic voltages did you check on the MLB?
kjchatman1
Member
i'm not familiar with the apple silicone boards. i checked 3v8_aon and ppbus_aon and both are present but the ppbus is only 12.1v
kjchatman1
Member
the amp meter show 5v .900 amps and i just let it sit for a few hours. that's must've charged up the battery because now it's booting but not charging. Now all ports show 20v .000 on amp meter but only with the charged battery attached
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So you should have problems on USB-C chargeing areas.
When machine boots (with battery), do you get USB activity and external video?
Check on all ports.
When machine boots (with battery), do you get USB activity and external video?
Check on all ports.
kjchatman1
Member
there's no activity on any of them. ug400 was visibly burned when i first started the repair and the first thing replaced
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Did you get it from same board model and same position?
kjchatman1
Member
i got it from a 2020 13" a2251
Not good...
kjchatman1
Member
i thought that any cd3217b12 would work. no? these are not programmed right?
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Many of them ARE; especially from A2141 and A2251.
OTP fucks tehnicians life.
logi.wiki
OTP fucks tehnicians life.
CD3217 and T2 Power on Sequence - LogiWiki
We have Apple MacBook and iPhone Diode readings and general fault finding information compiled by the leaders in this area
kjchatman1
Member
i wonder if using a brand new chip would make a difference
Don't waste time with new chip...
kjchatman1
Member
it won't enter dfu because of ug400 right?
Not sure.
UF400 is the one involved in DFU communication.
UF400 is the one involved in DFU communication.
kjchatman1
Member
so the only option to replace ug400 is to take it from the exact location on a donor board of the same model?
Yes, these chips are nightmare...
kjchatman1
Member
i got a spare board today and it did the trick. I hope someone will document how to program a new chip