820-01700-05 5V 0.00-0.01A on all USB-C Ports

2informaticos

Administrator
Staff member
If you are not afraid to change the NANDs chip, do it.
You can't lose more than time now.

I recommend to change U9580 and check its output before placing the new NANDs.
 
While I'm comfortable flipping NANDs, donor boards with 6x NANDs in a high capacity SSD configuration are extremely expensive, so I'm very hesitant to take the NANDs off my $275 donor board unless I'm confident this is going to work.

I've now removed all six NANDs, and replaced U9580 with U9080 for testing. Now I have 2.5V on PP2V5_NAND_SSD0, but every 15 seconds or so the output collapses to nearly 0V for about a second. I noticed that PPBUS is going from 12.6V to 12.3V on the same schedule, is this normal for a board with no NANDs? The power consumption on my ammeter is steady at 0.05A 20V. After digging out the burned fiberglass, there was a huge hole in the board and I had to replace pretty much every pad that was not ground with a jumper, so it's possible there's a bad connection to U9580, but I don't see how this would cause PPBUS to fluctuate and I'm pretty confident in my soldering.
 

2informaticos

Administrator
Staff member
T2 has its firmware partition on SSD.
Bad SSD will also cause T2 problems.

I recommend to keep the NANDs for other board repair.
This one may be unrepairable...
 
Thank you for your insights and advice on this project!

My hope is that because the T2 can’t find its firmware, the system automatically resets after 15 seconds and that’s why I see fluctuations in PPBUS and other rails.

So last question - Any idea if it’s normal to see some sort of an automatic reset loop when the SSD isn’t functioning, isn’t powered, or has been removed?
 
Update: I verified with a working board, removing U9080 caused the behavior described above. I will be proceeding with the SSD transplant.
 
Unfortunately I'm stuck in DFU after the NAND transplant, here's what I did:

-Verified that no NAND power rails were shorted on the donor board
-Replaced U9080 on the customer board, verified that all NAND voltages were now stable
-Moved 6x NANDs from an identical donor board with the same size SSD (1TB)
-Placed all NANDs in the exact same location as on the donor
-Replaced any small components that were knocked off, verified everything missing nearby was no stuff on the donor
-Checked for shorts on major NAND power rails, then powered up in DFU
-Verified that all NAND voltages were as expected

DFU restore gave error 4042 on the first attempt and 16383 on the second attempt. The progress bar quickly approaches the end of step 4 of 4, but then hangs for several minutes before producing an error. There's not much info online about these errors, I'm feeling totally stuck. I'm very confident in my soldering and pretty surprised this didn't work out, any suggestions?
 

2informaticos

Administrator
Staff member
As already said, nobody left positive feedback on the forum about NAND swap.
Same apply for T2 replace.
I appreciate the feedback from your experiment, but maybe didn't choose the best machine to do this.
 
I hear you... If I transplant the T2 from the donor board, could that theoretically work?

I see so many of these newer boards dead in the water and would like to raise the repair rate even if it takes throwing in some time and practice at NAND and T2 swaps, in particular this board is work about $1k when working.
 

2informaticos

Administrator
Staff member
I said, no positive feedback left on the forum.
People claimed to done it on Internet.

There is some information can't be copied; ID code is baked into T2.
 
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