WD1600BB dead - help!


I have a Western Digital 1600BB drive that just went dead. Reading from some other posts, I tried to reemove on of the diodes D6 on the PCB, but that didn’t revive it.

Please help.

here are the photos of my PCB:

DSCF5062.jpg DSCF5063.jpg DSCF5064.jpg DSCF5065.jpg

Any help would be appreciated on what I could try to revive my PCB!

Many Thanks

1 Like

Did you measure the resistance of D6 and R82? Was D6 visibly damaged?

Hi fzabkar,

Thank you so much for your reply.

Actually I was a little too hasty and removed D6 (de soldered) only to find out it was OK, it is not shorted. So i reinstalled it. D5 is not shorted either and the 0 ohm resitors that accompany D6 and D5 are good too because they give continuity. (I have a very simple meter which beeps when there is continuity and doesn’t when there is not…I am not able to set it to 200ohm scale, but if you think that is important I could borrow a meter).

I checked also D3 and D4 and they look fine (no continuity), as well as all the other 0 ohm resitors on the board - Ok too (all give continuity). I saw in another post the thing about cleaning the connectors with an eraser which I also did.

The drive is completely silent when I plug it in, no spin, nothing?

Is there something else I should look at? Tks

I can’t see any physical damage. The only thing I can do is to help you measure the onboard voltages, but that will most likely just be a post mortem exercise.

If the board turns out not to be economically repairable, then the easiest solution will be to transfer the 8-pin serial flash memory IC at U12 to a replacement PCB. The following PCB suppliers offer a firmware transfer service, either for free, or for US$10:


Otherwise, if you are not adept at soldering, your local TV/AV repair shop should be able to transfer the chip for you.

As for the measurements, you should do these with the board removed from the drive. You should also be very careful, as a slip of your probes can do major damage. Whatever you do, you must not damage U12.

You can start by measuring the voltages on each pin of transistor Q8 (near the bottom right screw hole). I believe these should be +3.9V, +5V, and +3.3V. The latter should be the Vio voltage for the flash memory, Marvell MCU, and SDRAM.

Next measure the voltages on either side of the R050 resistor between L2 and C3, to the right of the MCU, at about 1 o’clock. That should be the Vcore voltage for the MCU.

Lastly, measure the voltage on the anode pin (non-striped end) of Schottky diode D4 (adjacent to L2). This will be the -5V supply for the preamp inside the HDA.

If those voltages are present, then reinstall the PCB, power up the drive, and measure the voltages on each of the four motor terminals immediately after switch-on.

You could use either of the two ground pins in your Molex power connector as your ground reference.


You are like an angel in disguise! Wow and thank you for those pointers. It’s going to take me a while to measure those voltages but I will in the week to come and will report back.

Tks again and hope to be able to get this little drive ressurected!


Here are my measurements. Looks like D4 (anode, non-striped end) is giving me 129.5 mv ?? I have a good meter now analog, which would go to minus (negative) it such was the case.

What next?


Here is the photo, it appears it won’t display in my reply:

Thank you very much for the feedback.

You have confirmed that the Vcore and Vio voltages are OK. This in turn confirms that the SMOOTH motor controller has at least some sanity (it controls the regulators). I would also confirm the the zero-ohm resistor at L9 is OK. The voltage at its top end should be +3.2V. If not, then there will probably be a short circuit on that supply rail.

I wouldn’t be too concerned about the absence of the -5V supply. Some good boards will also behave in this way. I don’t know if this is because the MCU switches this supply off if it doesn’t detect a preamp, or perhaps the supply doesn’t like operating without a load.

My next step would be to install the PCB on the drive, power it up, and measure the voltages at the motor terminals. There are 4 test points marked E50-53 on the rear of the PCB. If the motor is trying to spin, then there should be some activity at these terminals.

I hesitate to say this, by you could also measure the motor current at the current sense resistor, R10 (marked as R270 on body). On the rear of the PCB, there is a corresponding unlabelled test point between E3 and E50. If you wish to use this test point, then you will need to be extremely careful that you don’t short it to the adjacent ground plane, otherwise major damage may result. You would need to use the 200mVDC or 2VDC ranges on your meter. The resistance of R10 is actually 0.27 ohms, so a motor current of 1 amp will produce a sense voltage of 270mV.

(Edit: I seem to have misunderstood the function of R10. I have revised my findings in a follow-up reply.)

You can also measure the -5V test point at E13 on the rear of the PCB, near the GND pins of the Molex power connector. Once again, shorting this pin may cause serious damage, possibly to the preamp.

BTW, I prefer a probe with a sharp tip, eg …


Hi again,

Checked the zero-ohm resistor at L9 and it is OK. The voltage at both ends is +3.2v.

I put the PCB back on the drive, powered it up.

Here are the measurements:

E50: 3.9mv

E51: 3.9mv

E52: 3.9mv

E53: 3.9mv

Point between E3 and E50: 3.9mv

E13: 164.7mv

Weird no?



I happen to have a working WD2500BB drive. When the drive is spinning, the voltage at E13 is -5.2V. The voltages at E50-53 are +3.9V (not 3.9mV) when measured on my multimeter. However, the voltage on R10 is only about 1mV. That is not at all what I expected. In fact the datasheet for an L7250 SMOOTH motor controller (not the same as ours) states that the spindle current is indeed sensed via an external resistor. Therefore it appears that our sense resistor, which is also grounded at one end, works in a different way, or perhaps it has some other purpose??? BTW, I also examined this test point with my oscilloscope and confirmed that it sits at 0V when the drive is spinning.

I also have another PCB, but this second one is faulty. Its Vio supply is OK, but its Vcore supply is absent (the MOSFET chopper transistor, Q6, has been cooked). This board, when powered up on its own, also has a missing -5V supply. Therefore it appears that the motor controller does not generate this supply until commanded to do so by the MCU, in which case I suspect that your board’s MCU may be dead. I would just confirm that there is no short between E13 and ground, with and without the board installed on the HDA, otherwise the preamp would be suspect. I would also verify that resistor R120 tests OK (0.12 ohms). It is located at about 4 o’clock to the SMOOTH IC, and forms part of the -5V supply.

In short, ISTM that your MCU is probably dead, in which case your most expedient option would be to replace the PCB and transfer U12 to the donor.


Thank you for  your reply. I checked R120 and it looks fine and checked E13 (on and off drive) and it also looks fine.

Do you think there is anything else I could fiddle around with to try and get it going, since it is already dead, not much to lose?

As for transferring U12, I have a pretty good soldering iron (with a nice tip), but I suspect you need to desolder each side simultaneously? How is it done, with a special kind of tip (I can change tips on my iron).

Anyhow, many thanks for your input. You bring to the do it yourself repair people a whole wealth of competent information and you give without asking for anything back. Let me know if there is something I could do for you i.e. do you have a store of some kind that I could  purchase a board from, or anything to give you in return.

If by “looks fine” you mean that there is no short circuit between E13 and ground, both on and off the drive, then the absence of a -5V supply at E13 would suggest to me that the MCU is probably dead. The only other possibility I can think of is that the board may be programmed to Power Up in Standby (PUIS), but in this case it should still show up in BIOS, but perhaps with a blank model number field.

As for desoldering the IC, there should be video tutorials on the Internet. A fine tipped temperature controlled iron would be a bare minimum rquirement, as well as a decent solder ■■■■■■. The professionals would use a hot air rework station. I’ve seen some people use Chip Quik.

To make things a little easier, you could [sacrificially] remove the IC from the donor PCB by snipping its pins close to the body with flush cutters, and then remove the pins one at a time.