The Sinclair QL Forum

Hmm - never come across a microdrive unit like this before....

FORMAT mdv2_
works fine

FORMAT ram1_mdv2
Works as expected (I have a Trump Card plugged in) - the cartridge even reads fully - no bad sectors

THEN ......

put the cartridge into mdv1

DIR mdv1_
Bad or changed medium...

put cartridge back into mdv2_
Bad or changed medium....

FORMAT ram1_mdv2
then will not read the cartridge

the cartridge has to be reformatted - at which point it writes and reads great !!

Now what the heck is mdv1 doing to the cartridge

RWAP wrote:Hmm - never come across a microdrive unit like this before....
FORMAT mdv2_
works fine
FORMAT ram1_mdv2
Works as expected (I have a Trump Card plugged in) - the cartridge even reads fully - no bad sectors
THEN ......
put the cartridge into mdv1
DIR mdv1_
Bad or changed medium...
put cartridge back into mdv2_
Bad or changed medium....
FORMAT ram1_mdv2
then will not read the cartridge
the cartridge has to be reformatted - at which point it writes and reads great !!
Now what the heck is mdv1 doing to the cartridge

Sounds like that HD drive I told you about! Seems exactly what's happening when the disk is placed in another drive - the disk is no longer readable from that point on.

Might be worth a DEL_DEFB to 'close down' slave blocks before swapping drives.

Rich,
could be that the MD erase circuitry is faulty. That operates with a separate head and is normally activated only when the current sector would be written to erase it first.
Apparently, in your drive, it's constantly activated. And deletes everything that passes by.
That could happen if any one of C51, D12, D14 or the erase head would be shorted to ground on the MD headboard.

Tobias

tofro wrote:Rich,
could be that the MD erase circuitry is faulty. That operates with a separate head and is normally activated only when the current sector would be written to erase it first.
Apparently, in your drive, it's constantly activated. And deletes everything that passes by.
That could happen if any one of C51, D12, D14 or the erase head would be shorted to ground on the MD headboard.

Tobias

All electronics can break down due to a number of physical, production and environmental factors. Magnetic can become permanently magnetised.

This use to happen on old Philips(TM) cassette decks after much use, and then needed deGaussing apparently, however there is much speculation that this was never needed (it depends who what and where you read), but might be worth a try if the electronics checks out.

Alternatively you might have a faulty felt pad that needs replacing, now where can you get those?