Any way to trick hard drive pcb to keep motor spinning?

[caphair]

i have a bad hard drive that I want to use for another application involving the motor. When I apply 12 and 5v from a molex supply it spins up, stops, spins up again then stops till I unplug and plug back in.

I know it's a stepper motor so for me best and cheapest method would be to use original pcb, I read online you can ground couple points to trick it for continuous spin but it wasn't detailed on how.

Anyone know how to accomplish this?

[SteveNielsen]

Re: Any way to trick hard drive pcb to keep motor spinning?

You don't say what exact drive it is but I doubt that matters, every working drive I've connected 12v and 5v to will spin up and run continuously. I suspect bad motor control circuitry on the board but you did say the drive is bad. Perhaps that is why?

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

Hmm maybe? I've read some will stop if they don't get feedback from the heads?

This is what I read online:

"You can use the original PCB that comes on the hard drive to power the motor. You will have to run a couple of wires to ground on some hard drive to trick the PCB in keeping the motor running. Some hard drive PCB's will allow the motor to spin continually and some will stop after a certain amount of time."

[stj]

Re: Any way to trick hard drive pcb to keep motor spinning?

you need the datasheet for the motor driver i.c.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

you need the datasheet for the motor driver i.c.

Is the ic easily recognizable? There are many ics on the board

[Agent24]

Re: Any way to trick hard drive pcb to keep motor spinning?

Usually the 3rd or 2nd largest one that isn't RAM. Biggest one is usually the processor. Likely near the motor connections.

Read the model numbers on all of them and look them up if you don't know.

Probably it has an enable pin or something that needs to be pulled low or such. To know what, you need the datasheet.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

I'm having a hard time finding the data sheets on some of these. What do you think?

[momaka]

Re: Any way to trick hard drive pcb to keep motor spinning?

Is the ic easily recognizable? There are many ics on the board

Give us a picture and hard drive model.
Controller is often in SOIC package, usually 16 or more pins.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

Give us a picture and hard drive model.
Controller is often in SOIC package, usually 16 or more pins.

I've provided a picture in the post above yours. It's a Seagate ST32122A

[Agent24]

Re: Any way to trick hard drive pcb to keep motor spinning?

That's a pretty old drive! I'm guessing it's the 23400109-533 by ST, but those numbers seem funny, like a re-marking. No datasheet I can see. Otherwise I got no idea...

Those 3 Motorola 8-Pin parts are probably the motor drive transistors though. If you can trace the board and find out what drives them, you'll probably find it, but it looks like datasheets might be a bit hard to find here...

[fzabkar]

Re: Any way to trick hard drive pcb to keep motor spinning?

@caphair, the headstack positioner utilises a voice coil servo, not a stepper. AFAIR, HDD steppers disappeared in 1991 or thereabouts. The date codes on your PCB place it at around late 1997.

The spindle motor appears to be a 3-phase brushless DC type.

Product manual:
https://cdn.badcaps-static.com/pdfs/...2d4eaf5356.pdf

The IS61C1024 is a 128K x 8 SRAM while the AT29C512 is a 64K x 8 parallel flash EEPROM.

https://cdn.badcaps-static.com/pdfs/...c2819d225d.pdf
(AT29C512)

I suspect that the array of 5 x 5R11 resistors may be the current sense for the voice coil while the 4 x 2R2 array may be the current sense for the spindle motor. The 3 Motorola 02N05Z (?) chips appear to be the drivers for each of the motor's phases.

I suspect that the CL-SH3302 is a Sampled-Amplitude Digital R/W Channel Device similar to a CL-SH3300. It would be connected to the preamp on the headstack inside the HDA.



The SC439566FU8 chip appears to be a special order by Motorola for Seagate, as indicated by Seagate's part number, 23400129-001. It may be the primary MCU.

Similarly, the STMicroelectronics chip (23400109-533) also appears to be a special order for Seagate. It most probably comprises one or both of the VCM and spindle motor controllers.

The CL-SH7640 Cirrus Logic chip appears to be involved with the IDE interface.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

@fzabkar
So is the STMicroelectronics chip the one I need to focus on?

And yes the the 3 Motorola 02N05Z (?) do appear to be the drivers for each of the motor's phases I traced them back to the motor contacts.

[fzabkar]

Re: Any way to trick hard drive pcb to keep motor spinning?

I suspect that any effort to obtain information for the STMicroelectronics motor controller will be fruitless. It might be worth trying to isolate the HDA contacts with a business card. Maybe the motor will remain spinning in the absence of a servo signal ... or maybe not.

Otherwise you might like to read some datasheets:

http://www.users.on.net/~fzabkar/HDD...r_Control.html

The L7250 is well documented and appears to be the precursor to the modern range of "SMOOTH" combo VCM and spindle motor controllers:

L7250, SMOOTH, spindle motor + VCM controller, ST Microelectronics:



The following drive uses the L7250 and has plenty of test points:

PCB layout - Maxtor DiamondMax Plus 9 ATA/133:
http://www.hddoracle.com/viewtopic.php?f=112&t=117

The following tutorial shows how to detect the spindle motor current for any drive:

Measuring VCM and Spindle Motor Current:
http://www.hddoracle.com/viewtopic.php?f=59&t=204

Some drives (eg Seagate's F3 architecture -- 7200.11 and later) can be made to spin up or down by sending commands to the drive's serial TTL diagnostic port. The well known DIY "7200.11 BSY bug fix" has a procedure which includes such commands.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

HDA Contacts?

[fzabkar]

Re: Any way to trick hard drive pcb to keep motor spinning?

Head/Disc Assembly.

I'm referring to the "Heads Contacts" in the following article:

http://hddscan.com/doc/HDD_from_inside.html
http://en.rlab.ru/doc/images/hdd_main_parts/PCB1.jpg

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

Oh, yeah that didn't work. I'm confused a bit by the links you've provided, I need to identify the current sense for the motor and then ground it?

[fzabkar]

Re: Any way to trick hard drive pcb to keep motor spinning?

I've endeavoured to provide links that help you understand how these motor controllers work. As you can see, the L7250 has registers which are controlled via a 3-pin serial port (clock, data, enable). These registers determine various parameters including the target RPM. Ideally you would hook into your own motor controller's serial port. The L7250 datasheet also has application diagrams which should illuminate the structure of a typical circuit.

That said, your controller is a different one, so my information is not directly applicable. However, you should now be able to see why your task is essentially impossible.

As for grounding the current sense resistors, don't do that. You will defeat any current limiting if you do this and will probably burn out the MOSFET drivers. I'm merely illustrating how the circuit works.

[caphair]

Re: Any way to trick hard drive pcb to keep motor spinning?

Oh ok thank you for that I appreciate it. I'll take a look at the links

[goontron]

Re: Any way to trick hard drive pcb to keep motor spinning?

I've endeavoured to provide links that help you understand how these motor controllers work. As you can see, the L7250 has registers which are controlled via a 3-pin serial port (clock, data, enable). These registers determine various parameters including the target RPM. Ideally you would hook into your own motor controller's serial port. The L7250 datasheet also has application diagrams which should illuminate the structure of a typical circuit.

That said, your controller is a different one, so my information is not directly applicable. However, you should now be able to see why your task is essentially impossible.

As for grounding the current sense resistors, don't do that. You will defeat any current limiting if you do this and will probably burn out the MOSFET drivers. I'm merely illustrating how the circuit works.

Serial enable is not that hard actualy. Its like JTAGing a Blueray player.

[fzabkar]

Re: Any way to trick hard drive pcb to keep motor spinning?

If your drive is expendable, you could try to increase the current drive to the spindle motor. I'm assuming that the 4 x 2R2 resistors (= 0.55 ohm) provide the current sensing, so you could try doubling the spindle current by adding an 0.56 ohm resistor in parallel with the array.

If the motor is spinning down because it is not achieving full speed within the required time, then perhaps this modification will give it a boost. Be prepared for some surprises, though. :-)