1984 Quantum Q540 hard drive sounds - This drive had NO platters, but I got it working!

Here's yet another crazy story. This drive was on French website leboncoin for a few months. The listing said it had no platters, that they were removed in the 90s, and pictures showed that it indeed had no platters but the heads looked like they might be intact. But I saw online that the Q500 series, even though it uses an optical encoder for positionning, also had wedge servo, thus I assumed it would probably never do anything so I wasn't buying it. Until last week when I talked to ‪@TheDiskMaster‬ on discord and he convinced me I should try. The drive was 8€ (16€ after shipping and site fee)

When I got the drive, sure enough it seemed like it couldn't do anything. I put platters just in case and still nothing. Until I found out jumper E3 disables using the wedge servo! I later found a Quantum documentation stating about E3 that "When jumpered, disables servos and causes the drive to use only the glass scale for positioning; for diagnostic use only." It's incredible that Quantum left us this option, and gave a chance to this platter-less drive to live again!

After messing with it some more, including swapping another set of platters in, I got it working good enough to boot DOS and Windows 3.1 using head 0-3. Sadly, head 4 does not work properly at all, and I have to wonder if maybe head 4 failed back in the day and that's why they took the drive apart and removed its platters in the 90s.

This drive sounds great, its seeking sounds are very unusual, but it is a very early voice coil drive from 1984 so that's not too surprising. The way it's constructed is quite interesting as well, with the magnets and the coil being hidden under a metal plate that has other things monted on it. Sadly the head locking part is broken in multiple peices so it isn't in there, but it used the same principle that Quantum still used on their drives even in the early 2000s : Using air from the spinning disks to move a plastic part out of the way. Because the lock isn't there, I need to be careful as the heads can very very easily get out of the landing zone.

The Q500 series of drives might very well be the only voice coil drive where a complete platter swap like this is possible thanks to using an optical encoder (which was a Quantum thing) and having that diagnostic jumper to disable using the wedge servo. Other voice coil drives would've used a servo surface and definitly wouldn't be able to seek at all if it wasn't there.

I'm glad that this worked out like it did, as even if it is far from perfect, it is a very nice addition to the collection that I did not have to pay an outrageous amount for.