820-4924 no SSD

[Kyle93]

Arrived intermittently not booting from internal SSD. Liquid damage all around U3740 area.

Replaced everything in the area but now cant boot from internal SSD at all now.

U3740 pin 6 3.2V pin 7 1.358V pin 8 0V pin 3 3.2V

U3740 has been replaced twice now. Is it possible both U3740 are bad? Should something else be checked?

 

[2informaticos]

Pin 7 should be steady 0V.
Check R3744/45 and all traces around.
Be sure to have good circuits to J3700.
Also check U3710/11.

 

[MOMOH]

what do you get on pin 4? be sure there are no broken traces too

 

[Kyle93]

R3744 is no stuff on this board and on a working board? R3745 is good

U3710/11 3.3V

Pin 4 3.3v

 

[2informaticos]

R3744/45 must be present at same time on the board.
The other option is soldered R3743 and R3744/45 not used any.

Alos, as MOMOH mentioned above, check if SSD_RESET_CONN_L is high.

 

[Kyle93]

Ssd_reset_conn_l 3.4v

 

[2informaticos]

Do you have R3744/45 on the board, or just R3743?
Check all the C371x caps and traces around J3700.
Also clean the connector pins.

 

[Kyle93]

Just R3743

Replaced all of the C371x caps just to rule out but no change.

Board has been through ultrasonic but no change.

 

[2informaticos]

Ultrasonic bath can clean corroded areas.
But also can break some corroded traces; and will nor rebulid that!
You must be very careful, as an ultrasonic cleaner without sweep option can make more damages on the board.
You must re-check all traces continuity and small resistors.

"Just R3743
--------------
R3745 is good"
What do you think?

 

[Kyle93]

Solved. Board originally only had R3743. Removed R3743 and put in its place R3744 and R3745