Help with built-in microdrives

[Factor6]

Hi, I've got some original md carts, but none of them work in my QL, I just insert the cartridge into any drive, type dir mdv1_ (or mdv2_), the motor starts but after 1-2 seconds it stops and nothing happens. The QL prompts some I/O error. Only some of the carts behave like this. Some of them dont 'stop' the motor, but run 'forever'.. with no success with listing directory or a try to reformat it.
The most annoying thing is that my old cartridges which worked fine, now, after trying those new carts, don't work anymore. Should I clean MD heads somehow? Or is there any other solution?

thanks

F6

[RWAP]

A few issues can cause this:

a) Wearing of the felt pad at the top of the microdrive cartridge - as this ensures pressure between the tape and the tape head - it may be one has disintegrated and left particles on the QL mechanism!

b) Dirty tape heads - use any tape head cleaning fluid, or even a cd cleaning fluid

c) the rubber roller on the left hand side of the microdrive may be worn or ridden up the shaft it sits on - there should be a tiny gap at the bottom of the roller (just enough to hold a sheet of paper) - if it is more than this, then you can push the roller down again. It may also have worn - in many cases, you can get away with turning the roller upside down as the tape only tends to wear away the top half!