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Quantum Prodrive possible repair


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I pulled my Prodrive LPS 40meg apart that went into the classic.

 

the rubber bumpers sit on the magnet posts that the screws go through. I had to remove the head actuator assembly to get at it, as its in a really tight spot. lol, I cleaned out the old rubber little by little and still couldnt get it all. Maybe some acetone I could.

 

after that, I stuck some plastic foam in there and presto. works like a brand new drive.

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I took a 80MB Prodrive ELS apart, and its rubber crash stopper is on the bottom under the platter.

 

So, I removed the head actuator assembly, Since it was a single platter drive it made things much easier. Removed the platter, etc.. carefully.

 

Took some goo gone and got rid of all that rubber. Used various layers of heatsrink to replace it. Its a bit harder, but its better than nothing at all. Re-assembled and to my surprise, the drive worked perfectly.

 

now THAT was nuts. I never rebuilt a drive down to that degree before. I will have to do a video on my next drive. i have 1 more ELS 80mb left which should be the same as well.

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yea i could do that. But i didnt want to use foam because it doesnt hold together that well. You have to think of the air berring currents inside the unit as well as the actuator bouncing off of it. Ill figure something out.

 

it was just a milestone to be able to remove the actuator, the magnets, AND the platter, and reassemble it and keep it working again. LOL

 

the problem was, I used a tissue to wrap the platter in so it dont get dirty/messed up while I worked on the drive. that was a bad idea because alot of little fibers got onto the platter. yuck. It still worked, but i dunno for how long. lol.

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Maybe. What i will do though this weekend when I get some extra time, is fire it up on the mac and do a LLF in drive setup. make sure it comes clean with 0 bad sectors.

 

What i might do is use clear silicone? I might dab that on there and when it dries, use a razor to shape it. Other option is buy new rubber idlers for cassette deck restoration, or printer pick-up rollers and just cut that down to size.

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Techknight, thanx for the tip on the head thing with the paper/ toothpick. I did not know that and its great information. And Awesome about your drive... I never looked inside one of the LPS drives but would assume they would be similar; as what you described with the bumper and post is how the other looked inside. But I did not have to remove the head.

I have not attempted to remove a platter yet. Is it hard to do?

 

Great idea about the silicone...would last long too.

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  • 5 years later...

I found this thread last weekend when I was attempting to fix an 80MB ProDrive ELS that would spin up, click and spin down.  I threw away a pile of these years ago but am slowly running out of good 50 pin drives so I figured... why not try to fix it. 

 

The issue on mine was not the rubber bumper, I think.  I'm not sure why but the head parks itself too close to the spindle and the white flat plastic piece keeps it stuck there when the drive powers on again.  I was able to stuff a small piece of foam insulation on the opposite side so that the head isn't able to park itself too far? and get stuck.

 

I don't understand why the white piece is there and I don't get why the head arm can get latched on it.  What gives?  So far my repair is working perfectly, the data on the drive was intact and I was able to reformat the drive and it seems to be working great.  Is that white thing even necessary?

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  • 68kMLA Supporter

The white thing is the parking brake. I think it is supposed to keep the heads locked in the parking position. It should flip over and release the heads once the platters are spinning.

If it doesn’t swing over it must be stuck.

I would check again if it is really not sticking to the rubber bumper. The bumper might still look ok but might already be sticky enough to hold onto the light plastic piece that only moves from the platter airflow. Not a lot of force behind that so not a lot of stickyness is needed to hold it.

Edited by Bolle
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  • 68kMLA Supporter

Problem is that the heads might move while the platter is still spinning up. Insufficient platter speed means not enough airflow to keep the heads from touching the surface.

I would guess that most drives are smart enough not to move the heads as long as the platter isn’t at full speed but the brake has to be there for some reason.

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The rubber bumper in question is attached to the magnet, correct?  I found one there and it's in good shape.  I understand that there's one under the platter too, but the head doesn't appear to get stuck there and it moves freely as long as it can't get stuck on that parking brake deal.  I will check it again.

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I posted in this thread about rubber replacement a fairly detailed description of what these bumpers do and where they are on both the ELS and LPS drives. I figure silicone of some sort would be a perfect replacement material for them. You can probably use silicone beads if you can find them; the bumpers don't have to be perfectly cylindrical, just with dimensions in the ballpark of the originals. I'd like to find something made of silicone shaped roughly like a glue stick that I could cut to size.

 

The "parking brake" is Quantum's AIRLOCK armature. Its function is to prevent the head armature from moving out of the landing zone in the event the drive experiences shock. It utilizes the air current generated by the spinning platters to move the arm out of the way once the drive spins up, and it's spring-loaded to automatically deploy when the drive spins down. You'll notice that in older drives such as the LPS, the lower capacity versions have an odd black plastic platter on top. This is because the air currents required aren't generated without two platters. However, this problem was solved in the newer ELS drives: the single-platter drives have a wicked-looking attachment at the top of the spindle that generates enough air to move the AIRLOCK armature.

 

The head armature really don't have any torque so the slightest stickiness to any of the bumpers will keep it from moving. Your drives are probably sticking on the bumper underneath the platters (if you use an ELS drive), though if the AIRLOCK armature doesn't move once the platters are at full speed, there could be something unusual causing it to stick.

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  • 1 year later...

I might have found a solution that does not require removing the voice coil top magnet. I simply use a water hose washer, the flat kind that's usually orange/brown. I cut about a quarter of it, and insert it between the two magnets, in the space directly to the left of the preamp PCB. Somehow the dimensions are just right. This piece of rubber fits snuggly by friction, and it prevents the actuator from touching the gooed crash stop bumper. I "fixed" two drives that way, one single and one double platter, and they both work. See photos below.

 

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  • 4 weeks later...

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