A1989 820-00850-A not booting

hgoncalves

Active member
Hi.

I have an A1989 820-00850-A that is not booting.

Client said it stoped working over night.

It has 20V, and seams to try to boot, but reboots at around 200 mA.

First atent of DFU revive fails (IMG1). But from that one, the system is in recovery mode, and I get the second error (IMG2)

Can you help?
 

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2informaticos

Administrator
Staff member
If no important data on SSD, you should try restore option, instead of revive.
Force it into DFU, don't try from recovery state.
 

hgoncalves

Active member
Hi,

I've just realized that the ports UB3100/200 only works with one side of the cable. If cable fliped, they don't work., and on those ports I only get 5V now (before I had 20V). In the other two (UB300/400), I get 20V.

However, on F3000/1 I have 0V, even when I get 5V on the USB-C ampmeter when connected to those ports. Does this makes any sense to you?
 
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hgoncalves

Active member
Hi.

Both fuses are good and their traces to J300 are also good.

U3100 diode readings:
USBC_XA_CC1 = 0.602
USBC_XA_CC2 = 0.606

U3100 diode readings:
USBC_XB_CC1 = 0.601
USBC_XB_CC2 = 0.608
 

2informaticos

Administrator
Staff member
Only one fuse gets voltage, depending which port connected.
If USB-C meter shows 5V, same voltage must be found on corresponding fuse.
 

hgoncalves

Active member
Yes, the problem is that it hasen't. Even switching the ports, and corresponding fuse, it shows no voltages on those two.
Besides that, these ports only pull 5V with one side of the cable. If I flip the cable side, the ampmetter stays black (no power).
Already tested a new port, but i get the same behavior.

On the other two ports / fuses, the behavior is normal, and shows 20V

Any idea?
 
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