The Sinclair QL Forum

Just asking out of curiosity: I had read posts in this forum referring to micro drives by their specific position, for example someone requesting to purchase drive 1 or 2. I also notice that on some QL's, the microdrive edges are keyed. Is there really a difference between drive one and two or would either work if the plastic edge was cut or filed away?

Pretty sure there isn't. I've certainly swapped them in the past and it was fine. I did nearly have to trim one down, but found a working correctly keyed one in the end. Some have flat edges, some have one square protrusion and some have 2.

Yep, as far as I know there's no difference between drive 1 and drive 2 - One thing you might observe is that drives that used to live in drive 2 position have seen much less use and so are potentially in better shape after all this time.

There's only a numerical difference between them. The microdrives and main PCB are part of the same panel during manufacture and this was always the case. This means the component identifiers (R106, D72, etc) are different on each one. The components and layouts themselves are identical.

When Sinclair identified noise problems caused by video and power noise near the back of mdv1, they did add a shield to it and not mdv2 - but this did not change anything on the unit itself.

They are freely interchangeable, except a keyed deck microdrive unit cannot be placed to the right of a non-keyed deck unit unless the keys are removed.