Microdrive Cartridges
I've read many posts regarding these, and now I have a couple of Microdrives and a few carts I can see what all the fuss is about, those felt pads.
Now this is what I know, there was a few people who attempted with little success to re-do the pads with ones out of cassettes, i also know that Ablex the company who made them and subsequently the people who now run that operation no longer have the means to make them again.
Is this format literally "dead in the water", can nothing be done to produce better, more reliable cartridges? Because if you're a bit of a hardware purists like myself (just got rid of the divide+, just couldn't live with it), I think that with better carts this format still has merit, I'd love to be able to order xx amount of brand new, recently manufactured carts as I'm sure others would too (that rubber roller inside would make a good spare part to order as well)
Now this is what I know, there was a few people who attempted with little success to re-do the pads with ones out of cassettes, i also know that Ablex the company who made them and subsequently the people who now run that operation no longer have the means to make them again.
Is this format literally "dead in the water", can nothing be done to produce better, more reliable cartridges? Because if you're a bit of a hardware purists like myself (just got rid of the divide+, just couldn't live with it), I think that with better carts this format still has merit, I'd love to be able to order xx amount of brand new, recently manufactured carts as I'm sure others would too (that rubber roller inside would make a good spare part to order as well)
Post edited by Macc on
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i doubt anyone will make new cartridges as its production would be costly and not enough potential buyers.
about the rubber roller, perhaps it can be found. I had to buy similar thingy for tape recorder in amstrad cpc 464 and it was in local electronics store-same size. works like a charm.
I think the RWAP people have a "cartridge reaconditioning service". I tried to repair some of them but all I got was a mess of tape around the table. I cannot understand how that design could work: when you pull the tape only some millimeters to have place to put the new "sponge thingy" (sorry, I don't know how it is named in English), the moment I put it back into the Microdrive unit, the tape becomes a mess in the little plastic roller.
My conclusion: unlike floppy diskettes or even cassette tapes, microdrive cartridges have aged very bad. Besides, their internal design make them hard to be manipulated by an user. A whole new internal design would be needed. Fortunately, the main component of a microdrive cartridge is still in production: video tape (but not for much time, I'm afraid).
So, as I'm not a hardware purist, I've decided that it's more convenient to get a Microdrive unit, remove all old electronics, and put a microcontroller with a SD card to hold eigth Microdrive cartridge images, so one SD-Drive can act like 8 Microdrives.
By the way: while searching info about this, it became clear that the 8 microdives limit is not a hardware limit, but software! With a COMMS_CLK period of 2ms, the chain could more more large... up to 255 microdrive units or even more.
you could make up some ribbon cables so you could stack them upside down into a huge cartridge wall.
[FONT=Courier New] +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | +----+-+----+-+----+-+----+-+----+-+----+-+----+-+----+-. | [/FONT][FONT=Courier New].-+----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+-' | | --,| | --,| | --,| | --,| | --,| | --,| | --,| | --,| | +----+-+----+-+----+-+----+-+----+-+----+-+----+-+----+[/FONT] [FONT=Courier New]| | +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | '-+----+-+----+-+----+-+----+-+----+-+----+-+----+-+----+-. | [/FONT][FONT=Courier New].-+----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+-' | | --,| | --,| | --,| | --,| | --,| | --,| | --,| | --,| | +----+-+----+-+----+-+----+-+----+-+----+-+----+-+----+ | [/FONT][FONT=Courier New]| +----+ +----+ +----+ +----+ +----+ +----+ +----+ +----+ | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | |'-- | '-+----+-+----+-+----+-+----+-+----+-+----+-+----+-+----+--->IF1[/FONT][FONT=Courier New] [/FONT]:DAnd plenty of amperes in your 9V line... Actually, that *is* the hardware limit. My point is that a modern microcontroller-based replacement could handle more than 8 logical units in one physical unit, if the ROM is prepared for that.
How was the maximum capacity? From the File format reference a perfect microdrive cartridge has 254 sectors, 543 bytes per sector, giving 137922 bytes (134,7KB) of total storage. Eigth microdrives would let the user access to 1,05MB of data. None impressive if we take into account that there already were floppy interfaces that allowed two 720K floppy units, giving 1.44MB of data, sustantially faster than eigth microdrives (but surely not so flamboyant as watching eight microdrives in action :D). With 255 microdrives (in one physical unit), the amount of accesible data would reach 33.54MB. Maybe too much for a humble Spectrum, but surely well received into the QL community :)
It'll probably need a little wheel or something to sense when the drive is running or not.
It will probably be easier to make something like this than messing around with tape. Although I can just see version 1 having a whole mess of electronics connected to it and then there is the small;) task of miniaturisation.
I thought of that too, but i thought of this:
- MP3 adapters work only in one direction: they only supply information to the magnetic head; working bidirectional complicate things.
- The space within a cartridge is very small. This couldn't be a "cartridge mod" hobbyist project, as custom pieces should be designed and made, for example, a magnetic head small enough to let the adapter be loaded thru the frontal hole.
Another possibility could be to mod the microdrive unit and feed the microdrive ULA directly (pins DATA_1 and DATA_2), removing the head pcb, and using the COMMS_OUT signal to know when the motor would be spinning. The new "microdrive cartridge" thus, would be internal, and only a SD/MMC card would be accessible to the user. That SD/MMC wouldn't contain a MDR image, but something that would resemble the strings of "1" and "0" produced in the FM modulation by the Interface 1.
or go for huge microdrive cube! ok, changing the cartridges would (usually) be challenging..
but at least one could build two of those walls.
Think of the NOISE!:-o
A symphony of whirring and crunching for 10 minutes! ecstasy! then microdrive not found :evil: 255 microdrives whirr down. what a coda!
Hmm, so that is the problem everyone fails to fix. I thought I was the only one who couldn't repair those pads. I've tried 4-5 different material for them, plastic to actual cassette sponge, but no avail. Somehow when those pads fell down from a mdr, the tape mess up. I bricked 5 cartridges until now, I'm not sure what to put as a replacement pad anymore.
Noise? Remember that there can only one microdrive active, so the noise will be exactly the same with 1 or 8 or 255 microdrives (although you could override this in software, the results would be inpredictable... maybe, with a custom routine, you can format all cartridges at once, or do a massive cartridge copier: read from one, write to many, as in Amiga disk copiers...)
Surely someone can solve this problem, or at the very least find out why the various fixes dont work?
you sure? maybe it's drive related thing. My drives are dodgy, maybe I should clean them and try again.
Due to the age it doesn't matter if they are 'never used'..the chemistry of the sponge still 'happens'.
It's a bit like record decks and anything with one of those belt drives (some cassette players too). The belt literally melts after a certain age...I've recently bought 3 record decks and a 20r old tape player and the belt was a black liquid goo.
I've kind of given up on my microdrives ever working again and have spent a small fortune on carts only to have 90% of them die due to the sponge.
Now to try formatting the other three!
Try it again in a week ;)
how about using a demagnetizer on microdrives? has anyone tried a demagnetizer yet?
I did, with a moderate success.
The same tool, as microdrive heads are actually audio stereo heads. The problem is how to put in contact the demagnetizer head and the microdrive head. For me, it was a matter of disassembling the demagnetizer, take the head which is attached with two wires to the demagnetizer PCB, and bring it closer to the microdrive head.
It could be that in order to save the cartridge you need to replace the sponge before it totally disintegrates.
This theory could possibly explain the low success rate of sponge replacement.