3x Seagate drives, no spin up but power flowing to motor

[Jamesg]

I lost several drives in a power event in ~2014, more details (here). I only care about 6x of these drives, these 6x which make up a Raid-6 array (thus, worst case, i may only need 4x of the damaged drives working to pull data)

For now this question is focused on the 3x Seagate 3tb drives. I DO HAVE some matching donor PCBs for these 3x seagate drives
Seagate 3tb ST3000DM001 (SMOOTH AAAAJ V5 / TWN8U217) 100664987 revb

I did the 8pin chip+donor PCB swap on 2 x of these Seagate drives, however they still do not spin up. I checked that all 8x pins of the chip are connected/soldered properly via test points - still no spin up.

( however I noticed when i apply power to the drive, and then take a dc voltage reading of the 3x "legs" going from the PCB to the motor/center of the HDD, i do see power flowing, and it appears to slowly increase as if its trying to spin up the motor. (ie it slowly increases/increments from 0v -> 5.5v over the course of about 5-10 seconds) - but the motor does not spin up, and there is NO sound or noise coming from the drive, at all.

Any suggestions or further points i should test? What does this mean? (thank you)
(I fear it means the donor PCB is now fine/fixed, but infact the HDD's motor is fried and thus requires an expensive cleanroom plater move/swap)

(note- i was able to recover 2x 3tb Toshiba drives, from this same batch/event just by doing a 8pin rom+donor PCB swap )

Thank you

[pepe]

attach a serial terminal and post log here. It might be informative...
pepe

[Jamesg]

attach a serial terminal and post log here. It might be informative...
pepe

thanks pepe- Im actually getting nothing at all from the serial output of these problem Seagate drives. I have several good/working 3tb seagate drives (drives un-related to the problem drive) , and i used those drives to confirm all is working well with my FTDI serial adaptor setup, photo of that output below.

on the problem seagate drive: I did take a voltage reading of its serial pins, and was seeing only 0.12 dcV on its TX serial pin (as opposed to the normal ~1.7 dcV on a working Seagate TX serial pin)

FWIW - here is output from a good seagate drive i used as a test of my ftdi/serial setup:

Test of a WORKING seagate 3tb drive, just to confirm that my FTDI serial setup is good.

any other ideas or measurements i should take? thank you

[pepe]

you should get some kind of terminal output after swapping the rom chip to the donor pcb. Either a boot terminal or some output from the bootfw should be output...
unless your rom chip is toast and it's shorting Vio to Gnd...
Check with a multimeter in continuity check mode (diode), pin4 -negative (black lead), pin8 - positive (red lead), let us know your reading.

pepe

[Jamesg]

Thank you pepe (my replies are below your questions / quotes - below)-

Check with a multimeter in continuity check mode (diode), pin4 -negative (black lead), pin8 - positive (red lead), let us know your reading.
pepe

Assuming i have the pin out correct (based upon the pin number in the image attached below, and i can identify pin 1 based upon its DOT on the chip and the DOT on the PCB)
when i measure continuity between pin4 and pin8 of chip - i get ~512 showing on the multimeter (and NO beep / NO continuity sound).

to be clear- i took this measurement, when the PCB was NOT powered up, and while PCB was NOT attached to the HDD body (ofcouse, but i just want to be clear)

pin out and where i took readings

you should get some kind of terminal output after swapping the rom chip to the donor pcb. Either a boot terminal or some output from the bootfw should be output...
unless your rom chip is toast and it's shorting Vio to Gnd...

I understand.
question 1- so i should get some kind of terminal output even if the PCB is powered up + un-attached to the HDD body?

(there is a always a chance that my FTDI is having issues with the 1.7v output as its set 3.3v, however i did get termnial output from other seagate drives of the same model) -
do note my prior comment above please: on this problem seagate PCB/drive: I did take a voltage reading of its serial pins, and was seeing only 0.12 dcV on its TX serial pin (as opposed to the normal ~1.7 dcV that i see on a working Seagate TX serial pin from which i AM able to get terminal output)

question 2- how can i test Vio to Gnd? (ie which pin # is Vio)? and do i check for it shorting while the pcb is powered up or without power?

note- i have confirmed that my solder points of the 8pin chip are good, via checking continuity from each of the 8pin chips legs TO corresponding test points on the pcb itself.

I have also added some photos of the problem PCB board

thank you again

Attachments

[pepe]

Things look right except the 3.3V ftdi adapter. Can you show what drive did you get terminal output from? (label, pcb)
does the donor pcb work if you restore everything?

pepe

[fzabkar]

question 2- how can i test Vio to Gnd? (ie which pin # is Vio)? and do i check for it shorting while the pcb is powered up or without power?

Vio for the PCB is the same as the Vcc of the ROM. Test for a short between ROM Vcc (pin #8) and ground (pin #4), with the PCB powered off. If there is no short, then measure the Vcc voltage (with the PCB powered on).