Replace Diskdrive in Panasonic FS-A1FX

Paladin (869)

14-09-2012, 12:09

I have a broken diskdrive in a Panasonic FS-A1FX
Already replaced the drivebelt, but the drive still gives errors.

Now I'm trying to replace it with an other MSX drive or a PC-Drive.

The drive i'm using is a brand new NEC FD1231H and a used (and working) drive from a NMS8255

I've tried the circuit and/or the rewireing of the NEC drive mentioned on:
Diskdrive Adapter Turbo-R

Untfortunatly it does'nt work. The MSX doesn't boot up. If I remove the RDY pin, the machine boots, but I get a Disk Offline.

Now I'm wondering if the drive and connector on the FS-A1FX is different then a Turbo-R drive.
Does anybody have a good and working approach to replace this drive ?

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Van bennyroger

Expert (74)

14-09-2012, 16:28

I have never seen the fs-a1fx, but my fs-a1wx uses the same as the turbo r.

Here is a link to google chache, could not get in the normal way at the moment..... for another guide.

http://webcache.googleusercontent.com/search?q=cache:tqAZVOU...

Van Retrofan

Paragon (1339)

14-09-2012, 22:08

Maybe you get the disk offline error because you used HD disks instead of DD disks? Did you disable the 1.44mb switch and did you cover the HD hole? Pin 34 is RDY and pin 2 DC?

Van luppie

Paladin (869)

14-09-2012, 22:09

Nope that is not the problem. I also test with a 720kb drive that is working properly in a NMS8255, so no HD and sure that it is DS0

Van RetroTechie

Paragon (1563)

14-09-2012, 22:25

Newer floppy drives may not provide a /RDY (ready) signal anymore, just /DC (disk change). Or have it, but no jumper to change setting or even an identifiable location on the controller board where that signal is found.

Troublesome in case your MSX floppy controller needs that signal (most MSX diskROM + FDC combo's do).

If that's the problem here, really 2 solutions: modify controller wiring and/or diskROM to do without /RDY signal (not so easy in most cases), or find another floppydrive that is compatible. For example an older type and/or one that's known to work in MSX machines.

Btw. does the drive LED light when you try to access it? If not, you've got DS (drive select) signals wired incorrectly. PC floppy drives normally respond to DS1 signal (drive B). Often hardwired - the cable decides how it's used.

Van luppie

Paladin (869)

14-09-2012, 22:26

The NEC drive that I'm testing does have a RDY signal. I altered the drive using the instructions on this Amiga forum.

Alternativly I use a MSX drive from a NMS8255 configured as DS0

Van Retrofan

Paragon (1339)

15-09-2012, 13:55

Maybe you have to remove the hardware swith as well which detects 1.44MB or 720kB disks even if you use DD disks. Look over here (Dutch) page 2 at the bottom.
Pin 34 should indeed have the RDY signal, so that must be correct. Do you hear the motor spinning and does the LED light work? I think your mod is nearly completed. Maybe some other Turbo-R users can help? And maybe pin 33 must hold the DC signal on the NEC intead of pin 2 as listed on MSX Pro? Does your NEC have the JA8 and JA9 jumper? JA8 must be altered from position 2 to 1 and JA9 from 2 (pin 33 GND) to 1 (pin 33 DC). You could disconnect pin 2 so you know fur sure it will act like a 720kB drive. Reroute your DC signal from controller chip to pin 33. (Maybe you don't need the jumpers if it has the DC signal on pin 33 on default). Hope this helps...

Van jltursan

Prophet (2619)

15-09-2012, 14:33

You can also try an easy test: Boot the machine always with a diskette inserted in the drive...

I've found that sometimes some machines refused to boot and freeze in the blue initial screen when no disk is inserted. Once inserted (no need to be a bootable one), they fully boot. Not sure; but it can be related to such RDY signal.

Van Retrofan

Paragon (1339)

19-09-2012, 11:50

Maybe other people owning a Turbo-R with PC FDD could post some internal and external pictures how it was done in their particular case? Please also mention the FDD which was used for replacement. (brand/type) Thanks for helping. It would be much appreciated.

Van luppie

Paladin (869)

10-06-2013, 10:34

After 9 months and replacing a drive in a FS-A1F I finaly saw the light and found a perfect way to replace the diskdrive in my FS-A1FX with a PC Diskdrive. This method had both the DC & RDY signals, so no separate switch to generate RDY or other tricks. For instructions look here. B-)

Van luppie

Paladin (869)

13-06-2013, 22:39

After I replace the drive with a PC drive, I also figured out how to add a 2nd drive to the FS-A1FX : Add a 2nd Drive