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Swapping control boards on a ST-251 drive

S

salamontagne

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Feb 27, 2010
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Harwinton,CT
For my friends "revive the XT" project, i purchased a st-251 drive from ebay.

His old one was DOA, and would not spin up. After verifying that the platters were NOT stuck, i put a bid on one on ebay, and its now on its way.

However, during our discussions, we keep wondering what *might* still be on the dead drive.

I removed the board on the botton of the drive to see how easily i could swap them out, and, while being a bit difficult with the connections, I'm sure i can swap a new board in.

What my question is...Will it work if, after verifying the new drive indeed works, swapping the boards? I imagine theres little differances inbetween the boards, except for minor revisions.

Is it possible todo this and get access to the information still on the drive, or will the controller force me todo a low-level format on it before i can access it?
 
If you could get to the 251 before the PCB went poof, the information should be intact with a new PCB. On MFM drives, the electronics are mostly dedicated to speed control and positioner operation. The read/write data pretty much just flows straight through. Your basic dumb-as-astump interface.

Hope it works for you. :thumbsup:
 
thanks for the words of encouragement...we still are unsure as to what killed the drive in the first place. I'll post back here once Ive tried the board swap.
 
Even with modern IDE drives, swapping the drive's circuit board is completely plug-and-play, as long as both drives are of the exact same model. However, if the drive doesn't spin up, it might not be the electronics at fault; the motor may simply be burned out, in which case a more advanced repair will be necessary. With proper tools, you could swap the platters from the old drive to the new one.

Believe it or not, hard drives still work even when the platters and read/write heads are exposed to the air; hard drives are never totally "sealed" and are always open to the atmosphere through filtered vents in the housing. Of course, if left uncovered, the platters will eventually collect enough dust to start causing errors, but even in a worst case scenario you should still get enough usable life left out of the opened-up, repaired, and re-closed drive to successfully extract all the data from it.
 
While it's true that the PCBs are usually interchangeable, note that there are two models of the ST-251, the 251 and the 251A which is somewhat different (and faster); those may not be interchangeable.
 
oh, boy, what did i get myself into?

oh, boy, what did i get myself into?

The labels on both drives (the dead one and the one i bought on e-pay) both list them as st-251. Is the "a" revision noted on the sticker?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360239792581&ssPageName=STRK:MEWNX:IT

Thats the one on ebay that i won...I imagine no one else bid on it because of the huge label on it marking it as "degaussed" :p

vwestlife, I'm hopeing to avoid swapping platters, but, after conferring with my friend over the phone, he claims the last time he powered on the machine, the PS fan didnt move, and he got the smell of burning electronics :p

From what i was inside the drive, there was a hex or torx screw on top of the platters...I'm guessing thats why holds them onto the motor...Has anyone written up a how-to on doing the platter swap? It looks like i might have to keep it handy...
 
MikeS said:
While it's true that the PCBs are usually interchangeable, note that there are two models of the ST-251, the 251 and the 251A which is somewhat different (and faster); those may not be interchangeable.
Click to expand...

I believe you mean the ST-251-1. The -1 suffix indicates the faster version of a Seagate MFM or RLL drive, usually with an average seek time of 28 ms instead of 40 ms.
 
vwestlife said:
I believe you mean the ST-251-1. The -1 suffix indicates the faster version of a Seagate MFM or RLL drive, usually with an average seek time of 28 ms instead of 40 ms.
Click to expand...
D'oh! Of course; it has been a while...
@ s: Yes, it would be plainly labelled; sounds like yours are both 251s.
 
vwestlife said:
With proper tools, you could swap the platters from the old drive to the new one.
Click to expand...

salamontagne said:
vwestlife, I'm hopeing to avoid swapping platters
Click to expand...

salamontagne said:
From what i was inside the drive, there was a hex or torx screw on top of the platters...I'm guessing thats why holds them onto the motor...Has anyone written up a how-to on doing the platter swap? It looks like i might have to keep it handy...
Click to expand...

If that course of action eventuates, note that while floppy drives have a radial alignment process (so that floppies are interchangeable between drives), there is no radial alignment process for fixed hard drives.

And so if the platters are placed into a different drive housing, it will be highly unlikely that the heads will be aligned with the platter's tracks. The required radial head alignment would probably require the use of an oscilloscope.
 
Got replacement drive in....DOA

Got replacement drive in....DOA

Well, I got the replacement drive in today....Didnt spin up, so i decided to look under the cover...

The attached pic shows it all...I dont know what kinda tremendous magnet they put this poor thing through, but its a tosty... and, its marked "251-1" meaning its probabily the newer version...I noted smoe differances (most notabley, the lack of a 2732 Eprom) and tried it on the dead drive...

I was so happy to hear its charastic clunk when it fired....So i know the new control board is at least doing some sort of drive init....

Unfortunely, both of my mfm/rll drive cards refuse to recoginse the drives....I know Ive got the cables right on the drive end, but the card end is not marked for eithor cable so i cant determine which is pin one....and stason.org is no help...anyone got a pic showing the proper connections on the st11/11r card?
 

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well, i got the controller to ID the drive correctly....unforunatly, i cant acces it in dos "invalid drive specifaction" and fdisk complains it cant access drive 2...

Is this because the control board for the drive is from an st251-1 or is it probabily just a non functioning drive itself? The bios didnt make me go through a low-level format, as it should if the drive is wiped clen, so i'm assumeing that theres stuff still on the drive...but i cant see it...

Anyone have any idea here?
 
should have shuit my mouth...

should have shuit my mouth...

well, after verifying the connections on the controller card, now the bios comes up and tells me its not initilized....crap
 
WOW, that eBay ST-251 was shot! Moment of silence for that poor drive...

EDIT: I just noticed you said that was a degaused drive. If the degausing coil cause that much inductive heating, you can bet it probably fried the electronics too...

I'll leave my original reply below:

Even if you're unable to access the data that was on the old drive when using the electronics from the crashed eBay drive, you may be able to low level format it to use it as a fresh drive. I don't know what was changed in the newer version (faster -1 model) you took PCB from or if it's compatible with the HDA of the old slower unit...so it may not LLF correctly either. If the electronics try to step that stepper motor faster then it's capable, things will corrupt REAL quick since there is no servo information to tell the drive whether or it stepped correctly.

I've owned plenty ST-251s and still have several of them all working great still. They're usually pretty good drives if you take care of them. If you end up not getting any of it working, let me know if you or your friend wants to part with one or both front cover plates, I have several Seagate 5-1/4 drives missing them. ;)

Good luck!
 
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Wow....I was just in your state a couple of nights for a show :p

Anyhow, I was able to get his old st-251 working w/ the circuit board off the ebay drive. Sadly, i was unable to extract any data off the drive...

Good news is, i was able to LLF the drive and have had it working overtime with no issues.

I can ship off the drive cover if you wish, no prob. I was trying to keep it as well as the carcass of the fleabay drive for a project, but as it is, i'm haveing my hands full dealing with projects here. I was planning on useing it to make a dimensional diagram for a clear lexan (plexiglass) cover, and possibly, some day in the future, make a usb converter and try and mount the thing to a wall. Would be a nice geek show-off to watch the heads seek back and forth.....

Ahem....its yours...PM me with your address and i'll ship the cover (and the whole thing out to you if you want) as soon as i get a spare momment.
 
Well looks like I have the same problem. I have an defective ST-251 board rev 003 from years back that I don't know what to do with. It spins up but I don't get the startup sound in this youtube video only the shutdown sound http://www.youtube.com/watch?v=OPoawKOHjQ4. In disk manager I get "Disk 1 fails RECAL or TEST-DRIVE-READY". I think it's the board. I actually have a working RLL ST-277R that makes the sound in the video.
 
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