Hardware Switch Won't turn but boots in Hekate

[Agilato]

Hello,
From my two years old NS repair pile i found slightly water damaged board with unknown history.
Board had a lot of missing components and after few nights of fixing it finally started to charge at 5v 0.46A.

Tho it won't boot: no logo, no battery icon... no signs of life.
I decide to check maybe it has corrupted NAND chip or something like that.
And on my surprise I was able to successfully boot in Hekate.
Made backups with no errors and info looks normal (has 9 burnt fuses).
Also executed briccmii.bin to make sure it doesn't have Auto RCM. But still nothing.
Tried to mount BOOT0 with memloader it stuck on message: BOOT section "ENTRY" pc=....
Board has basic voltages: 3.3v, 1.1v and 1.8v

I have feeling that something is wrong with FW and software aren't my strong side.
So here we are... Any ideas?

UPDATE 1:
- Found topic that looks like it's a RAM issue. Have a lot of donors around, will try to swap the ram.

UPDATE 2:
- Replaced the RAM and BQ same thing
- Replaced MAX IC console no longer goes in RCM, still charges.

Thanks you!

 

[ppzikos]

hi , i have ideas maybe it's wrong , but ... maybe not , change or reflow max77621 under the soc .

or test if there is 0.9V on the 3 caps of max 77621 when memloader is ON.

 

[Agilato]

UPDATE:
I replaced RAM, also as BQ unknown replaced it too.
No changes, behaves exactly the same way.

 

[ppzikos]

max 77621 is your friend. or not.

 

[Agilato]

hi , i have ideas maybe it's wrong , but ... maybe not , change or reflow max77621 under the soc .

or test if there is 0.9V on the 3 caps of max 77621 when memloader is ON.

Only have 3.8v, i hope i measured correct caps.

 

[ppzikos]

3.8V> the big caps is the input (Vbat or Vcharger) of dc dc converter , litle caps is the output and it's 0.9V

 

[Agilato]

ok, than there is 2 small caps under the chip, closer to the edge, one has 1.2v other 1.8v

 

[ppzikos]

there is 3 inductor , 3 big caps ( output 0.9V) 3 small caps (input Vbus) , the 2 very small one is 1.8 V from max77620 and the second maybe for start DC DC

 

[Agilato]

Both MAX 77621 IC's have on those 3.8v and 1.8v vdd's.

 

[ppzikos]

sorry i'm wrong , this is a big caps for output , and i have verified it's 0.9V !

 

[Agilato]

Yeah.... have only 3.8 on small caps... nothing else, on both MAX Chips.

 

[ppzikos]

warning on the second max is normal , because there is one max77621 for cpu in the soc , and other max77621 is for the gpu in soc , gpu is not started a this moment.

max for gpu is on left of soc , max for cpu is under the soc

 

[Agilato]

Replaced MAX from donor board, RCM no longer works.
Mask was a bit corroded, but overall i haven't found any broken traces.
Same voltage on the caps, console charging at 5V 4.6A, no Boot.

I have one more board around in exactly the same condition,
it came with dead MAX, was heating up like crazy, replaced no life.

 

[ppzikos]

the caps for output are no short on max77621 ? .

 

[Agilato]

the caps for output are no short on max77621 ? .

Nope. No shorts. On Both consoles. I think, may be i overheated MAX chips... not sure if 350-380(C) might do it.

 

[ppzikos]

with the quick 861dw i use 350 whithout problem.

I will check but I believe that max77621 is not mandatory to start in rcm. there must be an additional failure.
if the switch no longer boots into rcm check that the USB lines are still good? (diode mode 0.4-0.7V) and do you have the voltage 3.3V 1.8V and 1.1V?

 

[Agilato]

with the quick 861dw i use 350 whithout problem.

I will check but I believe that max77621 is not mandatory to start in rcm. there must be an additional failure.
if the switch no longer boots into rcm check that the USB lines are still good? (diode mode 0.4-0.7V) and do you have the voltage 3.3V 1.8V and 1.1V?

I also use Quick 861DW.

3.3v on pin 6 of MT?
Where can i measure the rest of the voltages? I used to know it few years ago, but now can't find the info.
With charger connected?

 

[ppzikos]

F3 1.8V
E2 1.1V
B5 3.3V , it's same of m92 pin 6

 

[Agilato]

Yes, on both board voltages are present.
Also i found other diagram which shows 5v, but i don't have 5v mb it's irrelevant.

 

[ppzikos]

if you have 3.3 1.8 1.1V and good data line usb at 0.4-0.7V in diode mode and no rcm sorry but i cant help you.

https://gbatemp.net/threads/switch-hac21-charge-ok-no-boot-no-rcm-detected-all-v-rail-good.588687/

Also i found other diagram which shows 5v, but i don't have 5v mb it's irrelevant.

it's an old mistake

tomorrow I test a motherboard without the max77621 to see what it will do , for me its too late (1;30 am)