WD7500AAKS-00RBA0 not spinning.

[MasterT]

Motor winding resistance is the same between each pair of pads on the motor power lines.

Rotor is moving freely. So no motor issue.

With isolated heads would still not spin. So it can't be the HDA.

On pcb inspection i don't see any burnt components.

I tried with diffrent rom versions but would not spin.

CPU gets warm. No voltage on motor power lines.

What could it be?

Attachments

[cpm1993]

Dead PreAmp on HDA maybe ?

[fzabkar]

Measure the resistances between ground and pins 1, 4 and 6 at the HDA connector. These are the preamp's power pins.

[bcometa]

Try PCB swap.

[fzabkar]

I tried with diffrent rom versions but would not spin.

Your PCB's external ROM (U12) is unpopulated, so did you replace the PCB, or did you reprogram the MCU's internal ROM?

Be aware that your MCU (88i6745) is known for "head mimic" faults.

[MasterT]

Dead PreAmp on HDA maybe ?

With isolated heads would still not spin. So it can't be the HDA.

Measure the resistances between ground and pins 1, 4 and 6 at the HDA connector. These are the preamp's power pins.

pin 1 = 2.2 ohm
pin 4 = 335.5 Kohm
pin 6 = 18.16 kohm

Try PCB swap.

I don't have one like this and time is of the essence.

I could order one pretty cheap but it takes a week to get to me.

I tried with different rom versions but would not spin.

Your PCB's external ROM (U12) is unpopulated, so did you replace the PCB, or did you reprogram the MCU's internal ROM?

Be aware that your MCU (88i6745) is known for "head mimic" faults.

You are right. I reprogrammed MCU's internal ROM with different fw versions because i thought maybe pcb was swapped and incorrect fw it the cause for not spinning.

Can someone confirm that WD7500AAKS-00RBA0 goes with pcb 2060-701474-002?

It could be entirely different pcb with different MCU.

Drive has been to a computer repair shop before, and they are notorious for trying pcb swaps.

Thannks.

[HddDonorMarket]

I have same experience
Probably short circuit connectors.

Last edited by HddDonorMarket on October 11th, 2019, 4:28, edited 1 time in total.

[bcometa]

Can someone confirm that WD7500AAKS-00RBA0 goes with pcb 2060-701474-002?

Confirmed. Easiest (maybe not quickest) solution will probably be PCB swap + ROM recovery/rebuild.

[MasterT]

20190206_224406.jpg

I have same experience
Probably short circuit connectors.

I don't think there are short circuit connectors. Voltages on pcb seem right.

I don't see anything burnt like in your case.

I also checked all capacitor and none has a short to ground.

Can someone confirm that WD7500AAKS-00RBA0 goes with pcb 2060-701474-002?

Confirmed. Easiest (maybe not quickest) solution will probably be PCB swap + ROM recovery/rebuild.

Thank you for confirmation. I'll just order the pcb and see how it works.

[HddDonorMarket]

Then Wring PCB or ROM my guess too

[MasterT]

Donor PCB + Original ROM = 100 % Sucess