Hi all, During my time at Sandy, I learned microdrives (the part inside the case, not the cartridge) were surprisingly reliable and fault-free. The only two faults that came up on a regular basis were dirt, and damaged capstans.
The capstan, for those not in the know) is the rubber wheel on the motor which contacts the tape. The microdrive capstan has one advantage over capstans from tape decks. Tape deck capstans contact a metal pin when in position. If left for a long time, the capstan rubber acquires a "dent" which makes the tape change speed as it passed through - also, it slightly stretches the tape. The microdrive design contacts a plastic wheel in the cartridge, so it only touches something when a cartridge is left in. However, some people leave a cartridge permanently in the drive when not in use, and this can cause problems eventually. The wires that enter the motherboard are just tinned stranded wire and quite fragile. I always soldered pins on these as a first act of owning a QL - often, soldering on the pins was quicker than trying to fit that floppy mess of bent wire. I have tons of these pins so if anyone wants some for their QL, I'll happily mail them at no charge. At Sandy, we also found that cartridges would become error prone if not spun once in a while. I got into the practice of, once a month or two, spinning up every cartridge through at least one full loop (about 20-30 seconds) just to prevent print-through and to redistribute the lubricant. You'd be amazed how often we'd get "mad microdrive" complaints and we'd ask them to send in the computer and the problem cartridges, and they'd ALWAYS have fingerprints, or the computer smelled of cigarettes. Smoking kills cartridges! So does finger grease. If you pen your case to clean anything, it's always a good idea to remove and refit the voltage regulator. That's the small 3-pin device screwed to the heatsink right behind the microdrives. It gets warm regulating the voltage, but a poor connection can also create heat, so reseating the regulator in its socket helps it stay cool. While you're at it, if you have any PC thermal paste/crease/arctic silver, replace that little plastic shim, if there is one, with a tiny dab of that and you'll find it transfers heat to the heatsink FAR better. SOME people would get a tiny fan, hook it across the +9v and ground pins, and have it draw that air out the slots at the back. Nice if you can make it fit, but I don't think it makes much difference - it moves heat, but doesn't make sure it's being generated efficiently in the first place - just addresses the symptom. If I ever designed a QL PCB, it would have a far better power supply (but then, the PCB wouldn't be long and thin like that - it would be a eurocard or double eurocard - 100x160mm or so. I would also give it a proper bus with 4 or 5 expansion sockets. Hindsight. I know this is obvious to many, but not to all, so my apologies to those who consider this obvious. Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
