** Home Computer Microdrives **

If you are trying to breath life into Microdrives on Spectrum, QL or OPD look here.
Used on Sinclair:- (Spectrum) via Interface One, (QL) two drives on board , The ICL OPD ( a much loved tool ).

Why Bother ? , the micro drive only offers approx. 100k of slow storage, and there are better options for all the machines listed above. But how do you get the precious data from your old microdrives to those Floppy disks. Hopefully you have a better chance once you have read this.

The basic Microdrive Media, it is in essence a small ( ?? m/m wide ) loop of Video Quality magnetic tape, approx. ???? long. Formed into a continuous loop, and driven past a read/write head by a single motor. The Media is supposed to have a limited life and some systems, included a pass counter, to log the life of the Media. It is true that if a Microdrive cartridge is starting to give errors, that it may be worn out, but I have cartridges that are now over 17 years old, run each time the OPD is powered up, and still perform error free.

Two things help to make this possible, first the drives are cleaned ( see the inset Image of the drive) and just look at the Dust particles. Normal dust is soft and jams in the drive spaces, but it can be removed. However grit will cause permanent damage, to either the Media or the head. So how to keep the unit clean, a blast from an air spray, once in a while, is all that it takes. Keep the media in a closed box, when storing it. Or even better leave the media in the drive, it forms a good dust seal on most designs of drive

See drive Image and simple schematic.

However the drive life can be improved with some TLC, and some common symptoms, repairs and tips, follow:-

A:- The single motor gives a long life but can develop electrical noise, from worn, damaged brushes.

B:- Read/Write Head ( Item Y ) can suffer from excessive wear ( see Picture for a good head profile )

C:- The single microswitch ( Item X in both Pictures ), can not only need adjustment to sense the cartridge Write protect tab, but also the contacts can fail.

( Item Z ) in the picture is the Rubber drive sleeve, although these seem to last forever,the passage of the tape can sometimes produce a groove in the roller. The good news is that this is usually at the top of the roller, and the lower half is unused and as such, still ok. Carefully pull the sleeve up and off of the drive shaft, turn it upside down, push carefully back onto the spindle, and in most cases not only does the drive stop giving errors. But the drive becomes much quieter in operation.

** Microdrive Cartridges **

Last but not least is the Microdrive Cartridge itself. Not a lot can be done with a worn out cartridge, but the image below shows what a good cartridge should look like, and its protective sleeve. The ruler gives size comparison, in 'cm' .

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