L6262 2.6 Troubleshooting

[avladov84]

Hello, I apologize if this is completely the wrong place to ask this question.  I've been trying to learn and soak up as much information as I can about PCB board design, components, etc through a restoration project on a very old hard drive.  But I am admittedly a novice here, and information on this chip seems so hard to find...

I have a WD400BB that fails to spin up, and I purchased a donor PCB that matches it, however this one also fails to spin it up.  I've confirmed using a different PCB, with the same 4-pin motor interface that the physical motor is functioning, which shows that the issue is with the board(s).  What is curious is that both the original and the "new" board exhibit the same symptom (coincidence?).

My troubleshooting so far has led me here.  I've been testing the motor controller, which is an ST L6262 2.6 chip.  I cannot find a datasheet on this component which has me stuck.  The closest one I found was the L6268, but it seems like the placement of the OUT pins has changed between these versions (R_SENSE seems to be switched with OUT_B?).  I've attached a screenshot below showing voltage readings on each pin, along with good continuity tests between those pins and the 4-pin motor assembly.  The upshot is that the chip is not sending any voltage to any of the OUT pins, leading me to believe that it's missing some input on one of the other 41 pins or there's some other fault occurring.

I'm hoping that someone here could help me understand where to look next.  I'm happy to collect more information if it would be helpful.

Thank you so much!

[Peter BENSCH · Accepted solution]

Welcome @avladov84, to the community!

Well, regardless of the fact that Western Digital launched the Caviar WD400BB back in 2001 or 2002 and the components on it are already a few decades old, at best the respective customer, in this case Western Digital, has documentation for such custom components. I don't want to take away your illusion and I'm extremely sorry that I can't help you, but you won't find or get any information on this either via your preferred search engine or at STMicroelectronics. I don't think anyone in the community would give out trade secrets even if they had them.

If the problem is solved, although perhaps not to your complete satisfaction, please mark this thread as answered by selecting Accept as Solution, as also explained here. This will help other users find that answer faster.

Good luck!
/Peter

[RhSilicon]

From what little I understand of HDD restoration, the logic board (PCB) needs to have the data from the DISK in order to work. It may be possible to transplant the memory or data from the EEPROM to the known-good logic board.

I've also tried repairing some of these HDD's and I noticed that the bearings can get stuck if left unused for too long. It might be more assertive to seek help from a forum dedicated to HDD data recovery.

I found these:

https://forum.hddguru.com/

https://www.data-medics.com/forum/forums/hard-drive-data-recovery.5/

[AScha.3]

come on, wd400 can find for 16$ , working condition. so if you want get a working, buy it.

but to learn about design, take something, still in production.

from STM ...take a nucleo board. simple example of WORKING electronics.

[RhSilicon]

I started learning with scrap devices too :television: :radio: :telephone:, around the year 1993, before the internet became popular in my country around the year 2000, with datasheets of each component available. Buying something that worked to leave it not working was illogical to me 😅.

[avladov84]

Thank you for your responses, a bit of a burst bubble, but I understand.  I was really hoping I could trace the issue back to something else on the board, maybe a blown cap, resistor, diode...anything that I could pull off the old board and try to bring it back to life.  Oh well...

@Peter BENSCH my apologies, I certainly didn't mean to request anything privileged.  I suppose for my own knowledge, are the datasheets considered as such?  When I searched for this chip originally, tons came up for other chips, including at component distribution suppliers, so I assumed it was generally available (though just no one had it for this particular chip).  Or do you mean that this one was perhaps custom built for WD and that's why it is so hard to find?

@AScha.3 @RhSilicon I suppose in some respects I went down the rabbit hole inside the rabbit hole. This drive was one that I just never tossed because I thought one day I might be able to tinker with it to get it working again.  I was so hopeful that just the PCB swap would do the trick and then just battle with firmware/bios.  I'm with RhSilicon on this though, leaving mysteries unsolved isn't in my blood 😀.

[Peter BENSCH]

Correct, this device was custom-built for exactly one customer and is therefore not only difficult, but impossible to find on the open market. The same applies to the data sheet and other additional information.

Regards /Peter

[xBruno]

Here  Datasheet for L6262 https://www.alldatasheet.com/datasheet-pdf/pdf/22557/STMICROELECTRONICS/L6260.html 

[Peter BENSCH]

Thank you @xBruno for this contribution.

However, your suggested data sheet is not for the L6262-2.6 (TQFP44), but for the L6260 (TQFP64). In this respect, the TO cannot do anything with it.

Regards
/Peter