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Recapped-Still having trouble

onlyonemac

Well-known member
Hi, it's me again!

I finally got round to recapping my Performa 475. My soldering skils are not the best, but I managed to do it without damaging anything :) .

However. I am still having trouble with it :'( . The recap fixed the whistling speaker and the continual sad maccing, but it didn't fix everything. The hard drive still keeps spinning down when I switch it on, and it is still ocasionally playing half of the death chimes before bonging happily.

It will boot from a floppy, and the RAM seems to work properly, but I'm a bit annoyed about the hard drive, and although the death-chimes-before-happy-chime is not a problem, it is still concerning me as to why it's doing it. I really shouldn't be.

Please help.

 

olePigeon

Well-known member
Do you have a different hard disk drive to test? The HDD could be dying, and may be what's causing your continued problems.

 

uniserver

Well-known member
Yup , the only issue left is the hard drive, it's bad, sorry,

Good news you recapped your machine, good job!

Maybe some one in the uk there will send ya a scsi hd?

 

onlyonemac

Well-known member
Sorry, no, I don't have another HDD.

It's strange that it could be dying, because it hasn't being showing any signs of data corruption, and when it is up and running, it stays like that for as long as I leave the power on.

Spiceyokoodo had offered me an HDD a little while back-I'll ask him if it's still around.

 

uniserver

Well-known member
No, it's not weird at all those old scsi drives go bad when they want too, yeah some times you can get them back going with some tricks, But it's better to get a drive that is reliable!

You could give it a hard firm wap with a hammer, you could throw the hard drive in the freezer for a while, you could bake it in the oven at 200 degrees for a while, take the cover off and hold the head over so it won't spin down,

But is all temporary fixes,

 

techknight

Well-known member
the only real fix is to remove the head assembly without damaging it, and re-lubricating the actuator shaft bering. Other quantum models is the park release lever. all depends on which model. If you take a quantum dead HDD that you dont give 2 shits about, you can feel the "grunt" or stiffness at the park position of the head. This is the issue.

Also the magnets loosing thier permeability over the years isnt helping. The servos are pretty lenient and will do anything to keep lock over adverse conditions, but if the magnets arnt strong enough it wont overcome the friction required to release from park. So the other option is to lubricate the shaft.

 

onlyonemac

Well-known member
How do I do all of this without getting dust in? I fancy trying it for what it's worth (the HDD hasn't worked now for ages, so I'm probably not getting my lost pictures back :( ).

 

onlyonemac

Well-known member
I'm definately not getting anything back :-/ . Unfortunately, I thought I'd give the hold-the-head-back trick a try before attempting to lubricate the actuator shaft. Of course, in the process, my clumsy finger scraped the top platter :I . The drive's well and truly dead now :( .

 

techknight

Well-known member
yea... you cant do that. You have to be VERY careful, and have an extremely steady hand. and in a dusty environment, you have to be VERY fast too! Unless you make yourself a "clean box" which is nothing more than a tupperware container with glued in-place gloves to operate on it, and a couple of 12v fans that are silicone sealed. One intake and one exaust, Both having a high quality HEPA on the ends so no dusty air can leak back in while your operating on it, and so you can pull all the dust out of the box before starting.

 

olePigeon

Well-known member
I have a 80MB SCSI drive you could have for free, but shipping would be cost prohibitive to the UK. I think it's a minimum of US $43. :-/

 

uniserver

Well-known member
i shipped an iphone to russia flat rate usps, it was like 16 bucks.

a HD should fit into a small flat rate box.

 

James1095

Well-known member
The medium box is a lot more expensive because you can make it weigh a lot more. I sent one to a friend in the UK several months ago and it weighed 22 lbs.

I wouldn't expect neodymium magnets to lose permeability but I haven't researched the topic. I would think it more likely that the problem is whatever holds the head assembly in the park position has become a bit too sticky. Either lubrication has gummed up or a rubber pad has turned to goo. If the magnets were weak I would expect seek problems since the response would be much slower than the servo loop is expecting.

While I would only do it as a last ditch effort, once in a while you *can* get away with opening up a hard drive, just don't run it with the cover off if you can avoid it. I fixed a 40MB MFM drive around 20 years ago which required removing the cover, and afterward it ran fine until I got rid of the PC it was in ~5 years later.

 
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