18-11-2013, 01:02 PM
It's now been thirty years since Clive released the ZX Microdrive onto the scene. based on a closed 6m loop of what was nothing more than thin cut video tape, the system boasted at least 85k storage per cartridge. Initially expensive, but cheaper than a 3.5" floppy (remember them?) the Microdrive found its way into the QL before being phased out when Amstrad took over.
After several months of fiddling with the system, and finding out a lot about the cheapness of some of the bits along the way, Microdrive usage has been whittled down to the following points.
1) The original data lead between the ZX Interface 1 and the first drive was made of a solid cable rather than the nicer stuff used in IDC leads with the result that the data wires were prone to fracture and ultimately data transfer failure. Nothing unusual to get a message "Microdrive not found", wiggle the lead, and all would be well again. Replacement leads are easy to make up but getting the PCB edge sockets has been an issue, they have so far only been sourced from HK, and although initially cheap you can only buy in batches of five. The IDC lead is any old bog standard stuff but not too long due to data issues. A rather telling state of the UK electronics industry when you have to go to the far east for a part.
2) Treat all used cartridges with suspicion until you know better. Old cartridges have a habit of seizing up in use, usually due to disintegration of the foam pad under the read head. The foam attaches itself to the tape, gets dragged in the cartridge and that's the end of that. If possible, remove the foam, it will do long term damage to the cartridge in operation.
3) Cartridges used in QL machines run 25% faster (note 2 above) and are not cross compatible, date or otherwise, with the Spectrum.
4) Even brand new old/new cartridge stock must be considered unreliable until proved otherwise.
5) Keep it clean. A Q tip with a soak of head cleaner applied through the cartridge slot every so often and always when a cartridge fails will keep the system 100% reliable. As I found out, with the Microdrive system, cleanliness is everything.
6) I found a short program (available on the internet) that tests each cartridge before formatting does wonders to weed out the problems before you start saving data. The MD optimiser gets the maximum formatted space out of each cartridge.
For a thirty year old system, it works, its not perfect, there is better out there, but for the systems that were available at the time a rather elegant solution compared to the usage of tape recorders.
Pictures. 1) New/old stock MD cartridge, 2) the system complete, 3) 14 way PCB edge connectors ready for assembly.
After several months of fiddling with the system, and finding out a lot about the cheapness of some of the bits along the way, Microdrive usage has been whittled down to the following points.
1) The original data lead between the ZX Interface 1 and the first drive was made of a solid cable rather than the nicer stuff used in IDC leads with the result that the data wires were prone to fracture and ultimately data transfer failure. Nothing unusual to get a message "Microdrive not found", wiggle the lead, and all would be well again. Replacement leads are easy to make up but getting the PCB edge sockets has been an issue, they have so far only been sourced from HK, and although initially cheap you can only buy in batches of five. The IDC lead is any old bog standard stuff but not too long due to data issues. A rather telling state of the UK electronics industry when you have to go to the far east for a part.
2) Treat all used cartridges with suspicion until you know better. Old cartridges have a habit of seizing up in use, usually due to disintegration of the foam pad under the read head. The foam attaches itself to the tape, gets dragged in the cartridge and that's the end of that. If possible, remove the foam, it will do long term damage to the cartridge in operation.
3) Cartridges used in QL machines run 25% faster (note 2 above) and are not cross compatible, date or otherwise, with the Spectrum.
4) Even brand new old/new cartridge stock must be considered unreliable until proved otherwise.
5) Keep it clean. A Q tip with a soak of head cleaner applied through the cartridge slot every so often and always when a cartridge fails will keep the system 100% reliable. As I found out, with the Microdrive system, cleanliness is everything.
6) I found a short program (available on the internet) that tests each cartridge before formatting does wonders to weed out the problems before you start saving data. The MD optimiser gets the maximum formatted space out of each cartridge.
For a thirty year old system, it works, its not perfect, there is better out there, but for the systems that were available at the time a rather elegant solution compared to the usage of tape recorders.
Pictures. 1) New/old stock MD cartridge, 2) the system complete, 3) 14 way PCB edge connectors ready for assembly.
