[help] 820-01958 dead: 20v not switching

[mon2]

PP0v9_SSD0 is ok

This is a subjective comment. Meter in diode mode. Red meter probe to ground. Black meter probe on this rail. What is the exact diode mode measurement?

Does the measurement match the known good values in the referenced article?

PP0v9_SSD0: ~0.400-0.500

[phantomEVO]

i use flexbv+openboard data: this line should be 0,382 and i have 0,382

[phantomEVO]

i've found this


Once the T2 is powered from the above rails, it will read its ROM (U4770.) The T2 will then begin to start its boot up process, in which we will initialize the below rails.
PP3v_G3H: Normal voltage is ~3.0v. Produced from U7800, powers some PCH functions.
PP5v_G3S: Normal voltage is ~5v. Produced from U7650/Q7660.
PP3v3_G3S: Normal voltage is ~3.3v. Produced from U8210.
PP1v8_G3S: Normal voltage is ~1.8v. Produced from U8220.
The SSD power is then enabled to allow the T2 to boot BridgeOs.
PP1v8_VCCQIO_SSD0: Normal voltage is ~1.8v. Produced from U7800.
PP0v9_SSD: Normal voltage is ~0.9v. Produced from U7800.
PPVCC_NAND_SSD0: Normal voltage is ~2.5-2.7v. Produced from U9060.

Once the SSD is powered, and BridgeOs boots,

SO IS IT POSSIBLE THAT T2 doesn't enable those power rails for some reason? maybe because i have reflashed u4770?

[mon2]

You do have a voltage rail with netname PPVCC_NAND_SSD0 onboard.

What is the voltage to ground of PPVCC_NAND_SSD0 @ L9060?

[phantomEVO]

0v

[mon2]

What are the resistance and diode mode measurements for this rail?

Also interested in the voltage of the enable pin for this rail - PVCCSSD0_EN.

[phantomEVO]

no dfu anymore after reflashing u4770...

under the microscope, i've seen a solder blob between pin 1 of u4770 and pin 1 of c7920.

removed, but still no dfu?

maybe i've damaged u4770 "injecting" 1v from c7920 to pin 1 of u4770?
on u7901 now i have

pin 7 3,2v that goes to 0,5 tha goes to 3,2 in loop
pin 5 1,1v that goes to 0,5 that goes to 1.1 in loop
pin 1 unstable goes from 2,9 to 3,3 in loop
pin 2 1,8 to 0 in loop
pin 3 1,1 to 0 in loop

I WANT TO KILL MY SELF

[mon2]

Not funny but is funny. Kill the board, not yourself.

What is the resistance to ground of PP3V3_G3H?

[phantomEVO]

Funny for you 😭😭😂😂😂😂


resistence to ground of ppbus_g3h is 60k


At the beginning, one of the first thing i've done, before changing u7650, before changing cd3217etc, was to backup u4770 and flashing it with a dump found online.




So until now, i have had u4770 “working” with a dump




No i have those strange voltage (i Think it's impossible to have 3v in a line where i should have 1,1v!!) after flashing the original backup,..,





removing u7901, 3,3 come back stable

as soon as i resolder it, or even another one, 3,3v come back unstable

[phantomEVO]

This is the situation in this Moment:

I have 20v on both port even with power supply only

And 3,3 unstable….

Seems like a bootloop


https://www.dropbox.com/scl/fi/mid7t...=qlwapj9j&dl=0

even other power rails like 1,8v have the same behaviour

[phantomEVO]

This is what i see under thermal camera

I want to commit suicide




Please mon…give me a hope




https://www.dropbox.com/scl/fi/ik7cy...=lyg5ct1b&dl=0

[phantomEVO]

i repeat, if i remove u7901, 3v3_g3h become stable, but it doesn't switch to 20v,
if i solder u7901, 3,3v (and others voltages) become unstable but it switch to 20v

when u7901 is soldered

ihave

P1V1SLPDDR_RAMP 3,24v that goes to 0 in loop
PP1V1_SLPDDR 1,1v that goes to 0,5 to 0 in loop
PP1V1_SLPS2R 1,1v that goes to 0,5 to 0 in loop
P1V1_SLPDDR_SOCFET_EN 1,8 that goes to 0 in loop

[mon2]

Have to run around for groceries and have a date to fix a furnace today...What is the resistance to ground of this U7901?

Would you have a 100% known good U7901 from a donor? To me, this load switch is defective or the load is. What is the resistance to ground of PP1V1_SLPDDR?

[phantomEVO]

i have already changed it with anothe from a donor board without luck

in diode mode all pin are ok...

[phantomEVO]

reflashing t2 rom with a dump from internet, i'm again in dfu, but it doesn't switch to 20v.

i'v tried revive and restore, but still error 4014.....


maybe it's normal that it is in dfu mode with "Non original" firmware and consequence is that it doesn't switch to 20v and MUST BE RESTORED...but restoring i have error 4014 (t2?!)

otherwise with original firmware it switch to 20 v because MAYBE i've fixed all main power supplies but that i have other problem (t2 that become hot?)

i wouldnìt like to give up...

is it possible that the solder blob between pin 1 of u4770 and pin 1 of c7920 has damaged t2???!??!?!?!

i'm very scared

[mon2]

Monitor the spi lines for activity on the T2 ROM. The T2 is the SPI bus master so activity on these lines will confirm that the T2 is trying to boot.

Yes, the board will be in DFU mode after ROM flashing. Watch the YT video by master Liu on the U-Bos2 tool. He does exactly the same.

[phantomEVO]

ok, so we are at the starting point: i will flash again the rom with my backup, so i don't need to reflash in dfu.

in this scenario, i will have 20v on both port with the motherboard that (seems) try to boot the reboot it self. in fact i have the main power rail that appear and disappear

you can see it here

https://www.dropbox.com/scl/fi/mid7t...=qlwapj9j&dl=0

in the same time i have this scenario under thermal camera

https://www.dropbox.com/scl/fi/ik7cy...=lyg5ct1b&dl=0

t2 hot and pm "sparkling"....

i don't know how to go on..


ps monitor the spi lines HOW? with oscilloscope? it is a mistery tool for me: i have it but i don't know how to use it

[phantomEVO]

so what can i do? so? should i reflash it with my backup to have 20v "In reboot" mode?

[phantomEVO]

I repeat




With original rom, i have 20v and a sort of boot loop (Main power rails appear and disappear)




[URL unfurl="true"]https://www.dropbox.com/scl/fi/mid7t9ubqjcjxxvz1933s/Video-05-01-25-16-23-58.mov?rlkey=vdgsjwfr3fxcv705lqrucnhoj&e=1&st=qlwapj9j&dl=0[/URL]

And the machine is not recognized in dfu










With Rom from Internet I have 5v with stable voltages , machine recognized in dfu and error 4014 at the beginning of the restore




And this behaviour under thermal camera




[URL unfurl="true"]https://www.dropbox.com/scl/fi/ik7cyevfxhhpqys09w6de/Video-05-01-25-17-05-19.mov?rlkey=yezd24vzetcua8qinvebq7l58&st=lyg5ct1b&dl=0[/URL]

[mon2]

Try another known good cable for the DFU. We use USB 4 type C cables.