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Canon 5.25" drive with stuck head carriage

drykid

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Joined
Jul 18, 2012
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Am trying to bring back to life a Canon 5.25" drive with what looks like a stuck head carriage. Not only does the head carriage not move at all when in use (although the disk itself spins), but I'm unable to move it manually no matter how much force I apply.to it. It seems to be absolutely jammed in place. My guess is that someone has tried to lubricate it at some stage with something that has since dried up completely. Am at a bit of a loss what to do really; short of hitting it with a hammer I can't think what else I can do to get the thing to move. One thing I did establish is that by loosening the two screws at either end that hold the rails themselves in place I found I could manually rotate the rail on one side relative to the carriage but not the other. So it only seems to be jammed on one of the rails as far as I can see, but obviously that's more than enough to stop it moving.

Any suggestions? Also can someone confirm that I should be able to move the head carriage manually on a model like this?
 

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Why not try a few drops of Alcohol on the rails to see if that loosens up the rail. I usually clean the rails with
Alcohol and a cotton swab. When they are clean, use a few drops of Dri-Slide, a Motorcycle cable Lubricant that
does not attract dirt. The Dri-Slide will last for years and is also good for Scanner Rails. Most Motorcycle
Shops carry Dri-Slide. A small can will be a lifetime supply.....Although I'm on my second can.

Larry
 
The drive rails look pretty clean to me--certainly not grungy enough to prevent the carriage from moving. I suspect that the stepper motor with the capstan is seized up. Try rotating the capstan directly. If it doesn't budge, you may have to remove the motor and see if you can get it working again.
 
The drive rails look pretty clean to me--certainly not grungy enough to prevent the carriage from moving. I suspect that the stepper motor with the capstan is seized up. Try rotating the capstan directly. If it doesn't budge, you may have to remove the motor and see if you can get it working again.
I don't think it's the stepper motor, mainly because if I loosen the screws holding the rails so they're free to move I can't even rotate the rail relative to the carriage (on the side with the motor anyway, the other side does rotate.) If the stepper motor was seized then I can see that it would prevent the carriage sliding backwards and forwards along the rail, but it shouldn't have any effect on the ability of the rail to rotate. So I think whatever someone has used to lubricate it in the past is stuck between the carriage and the rail and has seized it solid somehow.
 
Interesting--usually with grungy hardened lube, the action is sluggish and limited, but you can still move the carriage. Well, have at it--it'll be interesting to see what the real problem is.
FWIW, I've had brand-new 3.5" drives with hardened factory-applied lithium grease on the worm here. A bit of a surprise when the drive doesn't work right out of the factory-sealed antistatic bag.
 
I agree, the rail should spin, probably sleeved carriage bearings that have corroded (rather than just plastic running on te the rail, looking at one on Ebay, it does look as if they have a metal sleeve).

No option but to strip and force it out and hope you can polish it.

I take it, it has a tension band connected to the stepper motor ? If you undo this, you will have to setup track zero alignment again (which is doable with a scope and a working floppy, but a pain)

I would undo the clasps holding the rails then grab the end of the stuck rail with pliers (only on the bit under the clasp as you will probably mark it) and while holding the carriage, turn the rail until its free then pull it out. Polish it with paper & a bit of brasso and run a tip of a rag into the carriage and polish that too. Lub and reassemble.

Be carefull that you dont bend and damage or snap the tension band, they are virtually irreplaceable (I did make one once, it was hard and never quite worked properly).
 
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Yep, the plastic of the carriage doesn't touch the rail; there's a metal sleeve that makes the actual contact (well three sleeves actually, two on the rail closest to the stepper motor and a third one on the other.) What you say about corrosion sounds plausible.

I tried following your suggestion but I just couldn't get a good enough grip with the pliers and they slipped; don't think I actually damaged anything but it was a close thing and it's put me off attempting it again. Trying to grip something with a circular cross-section with pliers is a nightmare.
 
I think the only other option is to remove the carriage completely by undoing the tension band and both rails (and the head leads too), then you can tap the rail out.

Then you will need a program to step the head out and back to zero and then adjust the head until it reads (easiest with a scope on the output of the head amplifier, but you could use trial and error), you don't need an 'alignment' disk just as long as you have a previously working disk. There are a few quirks with setting track zero, but lets get it unstuck with as little damage as possible first.
 
If it's really the rails being corroded, I might be tempted to try squirting some penetrating oil on both sides of the sliders, upending the drive on its faceplate and letting it sit in a warm place for a day, adding oil as necessary (you can always clean up the excess). Then, using a small wood block and very small hammer, gently tap either side of the guides to see if they can be budged slightly. If you can get them to move a little bit, then persistence will eventually pay off.
Odds are, if you end up disassembling the carriage, my feeling is that getting things working again will be, er, problematical.

My .02 anyway.
 
A soak might do the trick :)

But I think your right, it needs a strip down. If it can be freed, then aligning on a 5.25 isn't too hard and very satisfying.
 
I did try putting oil around the sleeve area from both sides previously, but admittedly it was only for two or three hours. And it was just some 151 oil that I used because I had it to hand and because it said "superb at... penetrating" on the back so I figured it was worth a try. But there are better oils that are more suited to the purpose I'm sure. Anyway it made no difference but I suppose if it was a better oil and left longer then it might be a different outcome.

The hammer approach bothers me because there are three points of contact of carriage with the rail, two on one side and on the other. Obviously you can only tap one of the three points with a hammer at any one time. And my worry is that applying that kind of force to just one point while the other points of contact are still seized will more likely split the plastic carriage than free it. And I really don't want to risk that.

The other thing I noticed last night is that with regard to the rail that I thought was free, when you loosen the rail itself and rotate it relative to the carriage what's actually turning is the rail *and* the metal sleeve together. The sleeve and rail don't rotate relative to each other; it's just the sleeve rotating within the plastic of the carriage itself. So I've now come to the conclusion that it's seized on both rails after all.
 
Bugger.

Cant see much option other than to soak and tap (and hope).

I get what you mean about the one with the double bearing, you need a packing piece that fits perfectly between them when tapping.
 
I agree that it's a pretty bad situation. The plastic, having aged, is probably none too strong. I suspect that the sleeve may well be some nonferrous metal, such as phosphor bronze. If corrosion has set in, it may well have etched the rail.

As Gary suggests, create a piece that attempts to stabilize the 2-point rail contact and soak and tap. If things are really gummed up, the sleeve might possibly leave the plastic carriage and stay with the rail, which will not be a happy situation.

Is there something really special about this drive, or is it really just a bog-standard 5.25" 360K unit?
 
Is there something really special about this drive, or is it really just a bog-standard 5.25" 360K unit?
Yep, it came from a Yamaha sequencer that belonged to a well-known band (New Order) and was used in a lot of their concerts and videos. I know where I can get a (supposedly) working replacement, but the drive itself is maybe a third (by size / weight) of the sequencer itself and I don't therefore want to discard such a large chunk of what is - to me, anyway - a piece of history if I can get it working again.

I was discussing it on another forum and someone who seems very knowledgeable about these drives is willing to look at it in person so that may be the way forward. One possibility I'm considering if the drive really is shot is getting that replacement drive anyway, and maybe transferring the minimum of parts from it to the existing drive to make it work (maybe head carriage assembly and matching rails?) That way the unit would still retain most of the original drive.
 
Replacing the head and rails would be a simple solution, and if you have a spare on hand, you can then get a bit more violent on the stuck one.

Might be a bit more interesting to align though. Do you have another machine that uses a 5.25 drive ?

I use a BBC micro with watford diagnostics as it allows me to simply drive the head while testing.
 

Thanks, that's a MD211 which looks similar enough to mine that it would most likely work as a swap-in replacement. The actual one I have is a 790C though, and has one or two differences (on that MD211 the top circuit board is K36-0066-01 and on mine it's K36-0067-02 instead) so I'd probably stick to that model because I may end up swapping bits at the component level and if so then it's better if it's an identical one to be on the safe side. There is one for sale which does have the correct board, although on the expensive side and on the continent so if anyone in the UK has a working one they want to sell me then I'm sure we could come to some arrangement.
 
Replacing the head and rails would be a simple solution, and if you have a spare on hand, you can then get a bit more violent on the stuck one.

Might be a bit more interesting to align though. Do you have another machine that uses a 5.25 drive ?

I use a BBC micro with watford diagnostics as it allows me to simply drive the head while testing.

There are also Arduino-based projects that serve as drive tester/exercisers.

I'm not big on the "this spoon was used by Steve Jobs" type of thinking, but I know that some are.
 
Thanks, that's a MD211 which looks similar enough to mine that it would most likely work as a swap-in replacement. The actual one I have is a 790C.

Are you sure ?

The 790C looks like the model number of the spindle motor. What does the label on the chassis on the other side show ?
 
Are you sure ?

The 790C looks like the model number of the spindle motor. What does the label on the chassis on the other side show ?

You're probably right about that then. The one I've seen for sale that looks identical to mine (down to the circuit board number) is actually being sold as a BASF AG 6138. The reason for that is that it contains a sticker on it to that effect, but where the sticker is that says that on theirs is just an empty space on mine. But it's possible that mine is a BASF AG 6138 regardless even if not stickered as such. To be honest my main reason for calling it a Canon drive to begin with was that sticker on the motor, so if that only refers to the motor itself then I have no great reason to think it's a Canon drive at all anymore.
 
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