820-3536: Not seeing SSD unless if option key is held

[macRepairAmb]

Have a weird one. This is my first SSD troubleshooting ever. The board doesn't see the ssd, gives a question mark folder. But if i boot up holding the option key, it then shows the ssd. Also, if i boot into recovery mode, it ssd shows up. I can boot into the ssd OS when i use the option key.

Found corrosion around U3740, so replace chip, R3741, R3742 and C3740. Also, had to repair trace on C3740(1) due to missing pad. Still have ssd talking issue.

PP3V3_S0SW_SSD - 3.3
PP3V42_G3H - 3.4
SSD_RESET_L - 3.3
SSD_PWR_EN - 3.2
SSD_CLKREQ_L - 0.0
SSD_RESET_CONN_L - 3.4

Only measurements i found different so far was on C3714 to 3717, pads 2 were all reading 0v while pad 1 were reading 0.52. Compared to C3710 to 3713, pad 2 were all reading 0.3 and 0.39 on pad 1. Not sure what this means.

 

[2informaticos]

Did you try another SSD?
Also try fresh macOS install.

 

[macRepairAmb]

Yeah, appears i had fixed the original issue with the parts replacement. I just had to reinstall fresh OS. There must have been some file corruption when those chips corroded.

Anyway, thanks for the assist.

 

[piernov]

PRAM reset should fix that. Try 3× consecutively if 1 doesn't do it.