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Old 11-10-2021, 12:27 AM   #4
wnt2fx
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Join Date: May 2021
City & State: Berlin
My Country: Germany
I'm a: Knowledge Seeker
Posts: 16
Default Re: 820-01700 5v 0.25 a

Hey piernov. Thanks for beeing here ! Generally: t2 must come from identical Board ?

Now, I don’t think that the t2 is dead:

Today I picked up the housing with battery and after I installed the logicboard I suddenly had 0.07A @ 19v input on all ports.
I just connected fans, audio, power button and touch bar connections, not the battery yet ! So I was wondering if any of the flex connected where crucial to negotiate 20v an disconnected one after another. But still, logicboard in the housing, nothing connected and 19V. As usual on USB-C Ampmeter - 96W charger.
I can not explain why I have no more 5v 0.25A / 0.01 A on main port symptomatic.

The board power cycles it seems to me. Every about 20 seconds the drawn amps drop to 0.01 for a seconds and the fan wants to kick in.

With battery plugged the draw raises slowly to about 0.8A before the reset / cycling occurs. The battery has some charge at least. When I disconnect the charger the board continues cycling and has stable voltages (until 20 seconds :-) on the few points I measured. No DFU recognition.

ppbus 12.58V.

correct value and stable until each 20 seconds:

all SSD0 and SSD1 voltages
PP3V3_G3H_RTC_X
all major SLPs
PP3V3_G3H_T
PP5V_G3S

How can I find out if t2 fails to fetch efi from nand or if it does not get to that point because some malfunctioning circuitry is the root ? What rails are clever to check now and/or would it be wise to take out the nand and check it?
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