Hi, have this really tough A1425 2012 retina board. It won't recognise a SSD even with a know good drive and known good caddy. All power lines at J4500 are present as expected. How do I properly check the data lines?
By Caddy I meant the Plastic Caddy with its flex. Used one streikt from a working machine so that can’t be at fault.
I replaced R4506,4507,4508 and 4510 with ones from a donor as well as C4522 and C4525. I haven‘t replaced C4518 and C4517 yet as they are so close to the PCH.
In regards to the traces, I traced all 4 SATA signals to their resistors and then capacitors but its not possible to trace them beyond that so a bad PCH or not properly soldered PCH could still in theory be a unlikely cause for this, can’t it?
The drive isn’t APFS as it’s running Mavericks. None of the resistors were physically damaged or gave non nominal readings. same for the new ones. Don’t have any history on the machine. I did boot a copy of Catalina from usb and it didn’t recognize the disk.
Here are some readings without the drive plugged in:
SATA_SSDRHDD_R2D_N - OL
SATA_SSDRHDD_RC_N - OL
SATA_HDD_R2D_C_N - .330
SATA_SSDRHDD_D2R_N - OL
SATA_SSDRHDD_D2R_RC_N - OL
SATA_HDD_D2R_N - .360
SATA_HDD_D2R_P - .361
SATA_SSDRHDD_R2D_P - OL
SATA_SSDRHDD_R2D_RC_P - OL
SATA_HDD_R2D_C_P - .333
SATA_SSDRHDD_D2R_P - OL
SATA_SSDRHDD_D2R_RC_P - OL
The only changes I found with a plugged in SSD:
SATA_HDD_R2D_C_P - .333 --> .332
SATA_HDD_R2D_C_N - .330 ---> .329
SATA_HDD_D2R_N - .360 --> .357
Seem to me like more of the tolerances of my meter...
I don't have any board to compare, sorry.
I don't see any strange value, but I'm not sure what should get on all data lines...
If there is a serie coil, check if is close to 0 ohm (internal resistance); even on power rails.