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Jon183

Quantum ProDrive Rubber Replacement

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Hi everyone, I opened a quantum drive I had for testing purposes and I noticed that it had two tubular rubber pieces, one was perfect and the other one turned to goo.

 

I am wondering if there is a replacement part, not a piece of tape. Kind of like a stack of rubber washers or a full part.

 

This photo comes from the video below, the part he is holding that is covered in blue tape is what im talking about.

maxresdefault.jpg

 

Edited by Jon183

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I used old cassette pinch rollers drilled out, but YMMV.

 

They also make a rubber 3D printer filament so it can be done that way I bet. 

Edited by techknight

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Consider to look for a piece of rubber tube of appropriate size, as used in a chemical laboratory, or fuel hose from a garage. O-ring seals are available in nearly any diameter and thickness. You could use a stack of O-ring seals. You may choose the size, specified as inside diameter x cross section diameter (thickness), and the hardness, specified as Shore hardness, to order rubber rings with desired properties. If available as square washers, the stack might resemble the original part even better. But make sure the rings will not escape from the shaft and distribute into other places of the drive mechanism. Also, you could cut the tubular piece from a solid block of rubber, or cast a piece from silicone rubber or polyurethane casting compound.

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image.thumb.png.279b231e44dfd9e7f83e6accdb067812.png

Here is a diagram of the replacement rubber piece, I hope its sufficient, I pulled one out from a 40MB Quantum ProDrive, they seem to have two per drive. Please excuse my autodesk inventor skills, haven't used it in ages up until now.

NOTE: Measurements are metric and in millimeters, they may not be that accurate.

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Back in 2011, I had 200 rubber seals custom made for Casio diving watches  (DW-260, DW-210).     Cost me about $140 all tolled.

 

In that case, I had one remaining new one in the package and sent it to them and they scanned/measured it and then produced copies.

 

The company was Marco Rubber (http://www.marcorubber.com .   I dealt with Marty DeFrancisco, back in 2011.   No idea if he's still there.

 

Anyway, if you guys want to get some of these parts run off for the old drives, they can probably do it.

 

No, I didn't need 200 seals, but the reality is that getting a custom job like that is going to cost about that much whether you get 10 made or 100 made.

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You can do this very easy with a 3D printer and tpu filament (polyurethan). I use tpu with my ANET A8 for pole plugs (pole vaulting) and it works.

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What happens is, after decades of time and heat cycles, the bumper rubber de-vulcanizes and becomes a tar-like substance, glomming onto the armature when it is parked and refusing to let go under the relatively weak power of the armature's voice coil. A small nudge to the armature as soon as the platters are spinning at power-up is enough to break the armature loose and allow the drive to function normally, which it will do indefinitely until the next time the heads are parked.

 

So there are two models (at least) with this problem: the ProDrive LPS (pictured here) and the ProDrive ELS, which is a slightly different model from around the same era. The primary difference between these two models is that the LPS uses a hybrid servo system that combines an optical grid for coarse positioning with an embedded servo for final track seeking, and the ELS is a faster drive that is entirely embedded servo. The LPS was available between 40 and 230MB, while the ELS started at 40MB and eventually hit 500+MB (they may have changed the name to Lightning and/or Maverick on later drives, and may or may not have changed internals on these later larger drives). I like the LPS because they have a very distinctive sound to them, specifically the thermal recalibration that they perform roughly every 30 seconds whether you're actively moving data on the drive or not.

 

From what I have seen, the LPS is the easier of the two to service: simply remove the top set of magnets, remove the degraded rubber, replace with new shock-absorbent material*, and reassemble. From then it should work indefinitely, with the only real future failure points being spindle bearing failure or head crashes. I did notice that drives that have been stored in a humid environment will tend to develop corrosion on the top platter directly underneath the breather holes, so you may want to at least store your drives/Macs in sealed bags if they'll be sitting for a while.

 

The ELS is a different beast: it still has the one bumper on the magnet assembly, but it has another as well: underneath the bottom platter. This lower bumper is what causes the armature to stick. This bumper is also impossible to replace without removing the platters, which is a serious proposition on double-platter drives (the platters must be returned in their original positions relative to each other or the servo data will no longer align and the drive will not function). Single platter drives (40 or 80MB versions) are do-able but it's still a major operation that will likely result in failure unless the utmost care is taken to ensure complete cleanliness of the work area.

 

*The shock-absorbent material doesn't have to be rubber per se, but anything that's tough, non-shedding (felt is a no-go) and slightly cushy (hard plastic is a no-go) would work fine.  I would probably suggest something synthetic. Also, the specifications of the bumper rubber for both drives appears to be the same or close enough not to matter. With these bumpers you really just need to be roughly the same height and the same or slightly smaller diameter. They don't do anything critical once the drive is operating, however from my experiments I have determined that it is impossible to run a drive without some sort of bumper being in place: with out it, the armature moves too far inward at power-down and the heads scrape on the spindle, which not only contaminates the HDA with particulates but will also result in a catastrophic failure if one of the heads is grabbed by the spindle.

 

 

 

 

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