Vcore = 1.0V
Vio = 2.5V
Vio2 = 3.3
Vneg = -5.0V
0.47R = 6.3V
Cap A = 17.0V
Cap B = 12.0V
Other values in your labeled photos seem normal.

ROM_NVRAM
u7 = Pm25LV010 AE0847 M11910LG
u5 = 93C86WP B9126

Preamp disconnected still causes motor to spin.

I do have a pic of the other side of the PCB, and will upload later. Nothing looks burned or extraordinary, however.

Forgot to add: Mounted in an external USB case (Venus DS3), I have noted that this Hitachi spins down a few seconds after spinning up (probably because it "sees" it is not connected). I have a working version of a similar Hitachi that always spins (even when I disconnect USB). But I've seen this spin-down "feature" randomly or many working drives, too. Might be firmware related???

All your numbers look good to me, as expected.

If you are going to swap the board, then you will need to transfer U5, or its contents, to your donor.

The 0.47R resistor appears to be the current sense resistor for the voice coil. It finds a voltage level at the middle of the supply (12V / 2) when things are operating normally. If you measure the voltage across the resistor, then this will tell us if there is current flowing in the voice coil. Do this after the spindle has come up to speed. I believe that under normal conditions this voltage should be much less than 1V, probably around 100mV or 200mV.

I suspect that when you disconnected the preamp, the drive would have spun up and then spun down again after a short time. Am I right?

_________________
A backup a day keeps DR away.

Replacing the board ... been there, done that (see below) .... and, IAC, it won't tell me what's ULTIMATELY wrong, correct? Or what may have led to failure? Tho' for the latter, it may've been my fault. I was using a 2nd PSU to power a video card I was experimenting with at the time. No issues or pre-issues (errors, crashes, blue screens) ... just that upon power-up (after about 5hrs of PC being COLD off), I had the infamous "disk not found" message in BIOS. A while back, I did swap boards with another similar-month (and manuf. plant) drive ... it spun up but nothing more. The dual PSU arrangement was implemented carefully (dual PSUs are not uncommon in high-end systems), and no other PC component was affected.
This happened over 3yrs ago and, henceforth, the drive has been sitting in my parts bin after I abandoned service attempts ... following $$ second drive board swap. (Didn't know about board-only resources then!).
If anyone has ideas as to what may still be attempted with present drive/board, I'm all ears.

After you did this, did the donor drive still work with its own (donor) PCB?

What do you mean by "parking unit"? Are you referring to a load/unload ramp?

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A backup a day keeps DR away.

(1) Yes (but I don't follow your query: do you think the bad drive can damage the donor's PCB somehow??) Or do you mean the bad drive's PCB installed on the donor/good drive (as in a true PCB swap) .... in this case, I don't recall exactly... think it spun up.

(2) Yes, white parking ramp.

Forgot to add: after the defective drive spins up, one hears a very faint/soft chirp ... the type one hears ubiquitously in myriad healthy/working drives. Curious as to what causes normal chirps.

The voltage on both sides of the 0.47R is ~6.3V, so yes on very minor drop.

AIUI, under certain circumstances Hitachi drives may alter the contents of NVRAM on a foreign PCB so that the PCB no longer functions when it is returned to the original drive. I don't know if your model is one of these, or whether what you have done may have created such a problem.

As for the resistor, you should place your two probes on either side of it and measure the voltage that way. The chirping sounds like it may be the voice coil trying to move the heads off the ramp. To be honest, I don't know why your drive is behaving as it is. If the MCU is not commanding the headstack to load, then it must be because it is detecting a fault. Otherwise, if the headstack is trying to load, then either there is a problem in that area of the circuit (VCM, motor controller), or the heads are jammed on the ramp.

See Figure 3 in the following article:

Media Damage and Hard Drive Recovery:
download/file.php?id=6930

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A backup a day keeps DR away.

NOTE: ALL TESTS PERFORMED WITH DRIVE MOUNTED IN IN VENUS DS3 EXTERNAL USB CASE.

"Chirp", in re-listening, is an inaccurate audible description on my part. Rather ... by having my ears directly on top of the front cover, when the drive reached its "top" speed, it (whatever "it" is) softy clicks. I took the cover off and watched it. NO ATTEMPTED MOVEMENT wrt the head/swingarm assembly. There seems to be no jam, however. I can freely move the assembly in the ramp area. The audible click corresponds to NO physical movement I noticed with the cover off. Except in the Win XP system, the click is immediately followed by a spin down.
In a Win 7 PC, using Find a Device in Control Panel, I can get the drive to stay spinning. It does the click very much on time (every 15 sec of so) and stays spinning, unlike in XP. In the Win 7 system, a USB Mass Storage Device icon appears (my XP system detects nothing). The drive parameters are not populated, however. The Win 7 system keeps "pinging" the drive ad infinitum, I assume, which is why the spin-down never happens like on the XP.

I'm going to assume the main CPU is damaged internally. The swap board was probably diff. enough to not work.

I didn't mean for you to remove the cover again, as this introduces contaminants that may crash the heads.

In any case I'm out of ideas. Sorry.

_________________
A backup a day keeps DR away.

The contamination worry is largely an overblown myth, as noted by expert Scott Moulton. Do it in a clean environment, under a clear PVC bag. By design, the platters self-clean by centrifugal force., and there are channels and that pillow filter to help The biggest worry about working under the hood, IMO, is handling delicately-aligned internal components. Esp. that head assembly. Even with the ramp, manipulating is tricky.
As far as other's inability to help ... I had my doubts from the start ... the board swap 3 years ago failed.
You may have a chance to redeem yourself: I have a non-working Seagate 500GB from 2008 that's equally puzzling.

I am breaking down each point so it is easiest to comment on for me.

1. No, it is very valid. The average DIY does not realise the extent to which particles matter. The average DIY does not realise how many sub-naked-eye-seeable(TM) particles are around in the air. As for Scott, well he IS a pro, his experiences are good for a story, but not to say well all hard disks will survive because scotts did. I drove my car down the freeway doing 190KM an hour once, and it was fine. So no-one should have an issue doing it, crashes and speed fines are largely a myth.

2. An average DIY attempting HDD repair for the first time, further put at a disadvantage by fumbling around in a PVC Bag - I don't think it is a good situation.

3. So particles could be thrown under a head by force? even better way to finish a DIY very quickly.

4. With the cover off, the channel system, pillow etc. will have no effect. The particles will not magically flow through them or to the pillow.

5. Whole-heartedly agree, though I wouldn't sat "The Most" I would say "One of the most"

If there is no possibility of ever taking to a DR Company, then no reason to try whatever method you can, safe or not. But I wouldn't be giving people a false sense of security. Almost anything a DIY does will 90% of the time shorten or cease a drives life.

MHO.

Cheers

@13hm13, during the 1980s I used to work on 250kg hard drives that had removeable disc packs. These packs were routinely swapped by computer operators. Obviously this procedure introduced contaminants. However the drive had an AC blower motor which pumped air through a HEPA filter and pressurised the pack area. This meant that any contaminants should have been purged from the chamber well before the headstack left the parking ramp. Despite all this, I still witnessed several head crashes during my career. I recall on a couple of occasions having to rebuild a drive after all its 20 heads had been involved in an overnight crash. Initially it would have begun as a single head-to-disc contact, then the debris would have contaminated the other platters and crashed the remaining heads. Often you would see shards of broken heads and lots of aluminium shavings.

If I were you, and now that you have introduced contaminants, I would take some added precautions. Whenever I cleaned up the debris after a head crash, and after replacing the heads, I used to disable the voice coil before spinning up the motor, thus preventing the heads from loading. I used to let it run like this for up to an hour to ensure that any remaining debris had been purged by the blower. Your job is a little simpler since the headstack never moves off the ramp, ie you don't need to isolate the VCM contacts at the HDA connector, at least not unless you fix the drive.

Having said the above, I'm not a data recovery professional, but I do have experience in electronics, and I have done a few data recoveries in the past. That's about it. I can try to help you with your Seagate drive, but please start a different thread.

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A backup a day keeps DR away.

If so , factories would not need all that stuff in the assembly lines , they could just make the drives spin and "self-clean".



The experience on doing it is what makes the difference between doing the job and not - hence the cost for professional help or for the tools that make it a fail-proof procedure.

For working/sealed HDDs, I mostly disagree ... that's why heads stay stationary until drive has spun up. Even better for newer HDDs with parking ramps, mostly away from spin-up debris.
As far as serious/careful DIY attempts... a non-issue. I had a 2003 100GB Maxtor that had poor platter integrity from new purchase. Every few weeks, you'd hear a mild bang inside (particle hitting internal chassis), yet it cont. to function for years. I still have it in storage. And it works.

Getting OT here, and maybe I'll get nonlazy some day and start a topical thread about how certain DIY can substantially lengthen the lifespan of any HDD. This may include better cooling, vibration control and very clean input power. The latter are related to some of my DIY projects -- a commercial version (not my) may look like ....

(my o'scope confirms that a device like this can clean up + tighten regulation of input power, as well as noisy garbage going OUT of the drive, back into contaminating the greater PC environ.)

These generic tips, may indeed be ideal for failed drives ... devices that need all the help they can get, in order to get data off safely and completely.

If you really want to protect your drives from nasty power, then consider adding some overvoltage protection circuitry, eg two TVS diodes plus two fuses or polyswitches. Otherwise that device is just a bunch of low pass filters, ie a series choke plus a parallel capacitor. That's something you could put together for less than $10. It wouldn't be as pretty, but it would be just as functional. In fact I have an old 286-era tape drive whose Molex power cable had an integrated LC filter.

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A backup a day keeps DR away.

I assumed we were talking about opened drives re contamination... How do you contaminate a sealed drive.. unless you drop it in oil or something but that would never happen.

As for the Maxtor, you cant take one anecdote and apply it to other cases. Unless someone had the exact same drive, used it the exact same way in the exact same system for the exact amount of time.. and then it could still fail, simply "because"

I have had RAIDs where 4 out of 5 drives have failed within a month of each other and the last one is probably still humming along in a system somewhere on my network as BDC or something.

And your next message about the DIY, yes I agree that some of the suggested tweaks might prolong a drives life such as power regulation, cooling tweaks. But many drives go like champions without any of that. The HDD manuf's are very skilled in their circuit design, and a lot of the failures are people hooking them up to incorrect power supplies or the like. Its all very subjective, and IMHO taking such a lacklustre approach to a HDD is reckless.

But I still stand by the ultimate it is your drive, you choose what to do to it.

Okay, let's stick to the issue YOU seem to be most concerned about: Contamination via DIY (i.e., by a noncertified, private indiv.). If you have not seen/read Scott Mouton's opinions on this topic, Google that name and watch the YT videos.
My brief and controlled-condition cover removal was necessary for diagnostics: to determine whether the head/arm assemb was jammed. The polished and revealing surface of the top platter very effectively shows any accumulated contamination. Which can be carefully compress-air-canned away. If one still wants to argue the issue, I contend that the NORMAL, EVERYDAY operational vibration and mechanical "violence" of even a never-opened enterprise-level drive ultimately creates more fragments than does a serious and issue-aware DIYer briefly and carefully peeking under the hood. Keep the contamination issue in the context of the serious DIY engaging in forums and discussion like this and the issue becomes moot and academic.

BTW: Do you work in the DR industry? Or have ever used a DR service -- which has successfully recovered data for you? Or have read DR sales literature / ads... or have seen these companies' YT videos? I HAVE read/seen and, initially, been influenced by that marketing prose. I believed the scare tactics (like the cover screw torque issue-- see my post on that elsewhere). Contamination is a concern for DIY Joe Six-pack. But not folks serious enough to have sought out this forum, and have taken the time to research the topic, and have done a bit of reflection and CAREFUL experimentation.

Just because someone takes the time to make a video that contains advice, it doesn't necessarily follow that those claims are valid. The internet is full of really bad advice for DIY drive recovery (as well as good tips) but there is no "quality control" for content. You get a unilateral POV unless comments are allowed.

The benefit of forums like this is that you can get several opinions on the worthiness of a given procedure. That doesn't guarantee that you'll always get good advice, but the odds are much better . . .

Opening a hard drive without the benefit of a clean room is a form of Russian roulette. The drive might "survive" (for awhile), even with multiple attempts, but then it might fail, too. You can't predict the outcome accurately.

I would never store valuable data on a drive that had been opened in a clean room. Sometimes the process of breaking the seal contaminates the drive, and that contamination must removed. Processes for decontaminating drives are usually effective, but none (that I know of) are 100% guaranteed.

Although particles are ejected from platters by centrifugal force and the directed airflow when a sealed drive is spun up, the main reason why drives have to reach speed before loading is to provide lift for the heads. Contaminated drives may experience cascading failure of multiple heads, which proves that the filtration system isn't foolproof.

Take a junky drive that still spins and put it in the deep freezer. Then take the lid off and turn it on. You should be able to see a vortex of condensate spinning down upon the platter surface as it spins. Now imagine there are suspended particles in that stream, on a drive with working heads . . .

Now back to your drive. It doesn't appear that the voice coil servo circuit is working. Did you check for proper resistance of the voice coil?

Sometimes a bad head stack will be detected upon P.O.S.T, and the BIOS code will prevent the heads from seeking. Usually substituting a PCB with the wrong ROM bypasses the protection offered by the P.O.S.T. process. But that depends upon how that safety feature is executed by the drive manufacturer.

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Your response is confused as it WAY oversimplifies the issue.
To wit: One problem of adding in-line breakers, as you suggest, is finding the correct value. Either you keep breaking (very inconvenient!) or you choose a value too high and it doesn't break when it needs to (and that may very well be what happened in my HDD above as all the TVS's are okay -- same for my dead Seagate).
The SOTM device noted above is often used in somewhat costly audiophile systems -- systems built by outfits that furnish high-end A/V and HTPC systems to people willing to pay that much. And these customers have incomes and budgets that make it an acceptable option for them. I, on the other hand, find it more fun to DIY devices such as that -- my device also incorporates addit ferrite beads and (more to the point) inrush current suppressors*.
Getting very anal, one can replace those cheap ceramic caps on the HDD drive board with better-quality c0g np0 caps. And further bypass and filter each chip. Cu tape, grounded, isolates against RF/EMI, etc. etc.
Below are images of before/after rework of iPod-like device modded for high-performance (not mine), incorporating mods similar to mine for PCs:
before: http://imageshack.us/scaled/large/849/img0930nr.jpg
after: http://imageshack.us/a/img189/5139/dscf5884k.jpg
I also use very high-quality main PSUs. And that is plugged into three separate (cascaded) UPS/line-conditioner combos, one hospital-grade. But it takes days/weeks to design ... and (then) solder up (breadboard) some protos, and do tests (incl. o'scope metrics).

*With current suppressors, you have to be careful as you can add phase delay.