Mandatory replacements for every Microdrive

Rubber rollers
Every Microdrive that is used a lot, will need a new rubber roller.

Fortunately these are available from e.g. RWAP on SellMyRetro.com.

To replace them, the top plastic part of the Microdrive has to be removed.

Unfortunately two screws need to be removed which are under the metal faceplate.

The best way of removing the metal faceplate is to heat it up quite a bit, with either a hairdryer or a paint remover. But paint removers quickly may overheat the print on the metal faceplate, or melt the plastic. So be careful with that!

Electrolytic capacitors
There are two electrolytic capacitors in the Microdrive that should be replaced.

One on each side of the 7805 voltage regulator.

Use 1uF or 10uF replacements, and use tiny versions like 4x7mm, as larger ones may not fit.

It's no problem to use 10uF as it's for voltage stabilisation, so the higher the better.

Often Microdrives that have a lot of read/write or format problems, work as new after this replacement.

But there may also be other causes of defects or bad behavoir, like a bad tape head or bad ULA.