PC disk drive in Amiga 1200 help please

[Traindriver69]

Hi all
I have got a Sony MPF920-E E/131 pc floppy drive which with a mod should work fine in my 1200.but when it is in my 1200 the drive is clicking as it should but when I put a disk in the drive nothing happens no spinning no head movement nothing its like there is no disk inserted.
any help please I would love to get my floppy drive working.

[jlin_au]

Check the disk detection switches inside the floppy drive, one will match the write protect hole, one the HD floppy hole, and the third with be the inserted disk/disk change switch.

The inserted disk or disk change switch should be fully depressed and change its state when a floppy is inserted. This should tell the A1200 that a disk has been either been inserted or ejected.

Check the disk insertion mechanism for dust, blockages, jams that prevent the disk from being fully mounted when inserted.

[Traindriver69]

there are three swiches at the front but multimeter continuity says they are operating

[jolly11]

maybe this [ Show youtube player ] can help



or this: http://jope.fi/drives/

[solarmon]

I would recommend these great tools to use for testing floppy disk drives:

Amiga Test Kit
DriveTest

But it does sound like the Disk Presence sensor is not working and probably/hopefully just needs a bit of cleaning and lubricant - using contact cleaner or WD40.

This is a great video by on how to use DriveTest and and fix the Write Protect sensor, so the same can apply for the Disk Presense sensor:

[ Show youtube player ]

EDIT: I see now that you have stated the switches seems to be working. The video is still good for how to use DriveTest to troubleshoot floppy disk drives.

[jlin_au]

Check:
1) that your drive has the mods mentioned in the YouTube video (see jolly11's post). If not then you'll need to make the required changes yourself.

As per the video, I'd also use solder to short the HD detect switch PCB pins together so the drive sees the HD disk as a normal DD disk as the standard amiga floppy disk interface is unable read PC formatted HD disks at standard HD floppy disk rotation rates as the HD floppy bit data rates are too high.
The original commodore Amiga "HD" floppy drive (a special Chinon FB-357A drive) actually reduced its floppy rotation speed for HD floppies to get around this bit rate limitation. That was also why they read data off of PC HD formatted disks at slower rate than a PC would.

2) that the inner switch on the left side of your drive in the photo its changes conductive state when a floppy disk is fully inserted into the drive. If the switch fails to change state when he floppy has been fully inserted check that the carriage holding the floppy has fully dropped down into the drive. Dust or other debris blocking the carriage travel path has been known to stop the carriage from fully dropping down and fully engaging the detect switches.
see [ Show youtube player ]

[Traindriver69]

Hi all
Thanks for the replys spent sometime on it today and fixed it.
When I had cut the track being a very small area I had failed to notice I had gone a bit too far and also cut the track to pin 33 after soldering a link to the pin now working brillant.
Many thanks Again

[solarmon]

Originally Posted by Traindriver69

Hi all
Thanks for the replys spent sometime on it today and fixed it.
When I had cut the track being a very small area I had failed to notice I had gone a bit too far and also cut the track to pin 33 after soldering a link to the pin now working brillant.
Many thanks Again

Glad you found the issue and got it working!

You sure it is pin 33? Normally the odd pins are ground and typically joined together, so losing one ground pin shouldn't be an issue.