Catweasel And Drive Modification

[Loedown]

Double Density floppies are getting more than a bit long in the tooth. Amiga generally doesn't care what you stick in the drive, as long as it's Amiga formatted.

A simple modification to Catweasel drives makes them write quite happily to HD disks, whereas normally you have to put some tape over the HD hole.

I have three dedicated 3.5" drives, that I got new for the express purpose of using with the Catweasel, so I can modify them accordingly, but if you're using your normal internal PC drive as PC drive and Catweasel drive, you can't really do this, or you'll need to use another method which I will outline below.

Simply take the drive mechanism apart until you have access to the switches.




The black block thing at the upper left hand corner with the two plastic pieces sticking up is the write protect status switches, on the other side of the board ( not pictured ), there will be another one of these, but with only ONE piece sticking up, this is vitally important to know.

Taking a good iron and solder wick, desolder one leg of the switch, the legs that take signals from the switch are located either side of it, on my drives, they have three legs soldered, two are for the single switch, the other is used as mechanical mount to hold the switch in place. If you desolder the pin that is on the same side as that other one, then the switch is still mechanically sound, you bend the pin upwards to about 20 degrees, ensure there are no dags of solder remaining underneath.

      ***
1   --*o*
      * *
2   --*@*-- 3
      ***

Pin 1 is the mechanical strengthening, pin 2 is the one that should be desoldered and pin 3 is the other side of the switch. The @ represents the remaining switch, where the o represents a hole, or if the drive manufacturers were feeling lazy, this may have a switch in it too, but it won't be connected, if you're still unsure, check a disk with the drive to see which switch you should be modifying. The side of the disk you want is the side with the hole by itself, no little plastic slide for write protect.

If you want to use the drive as both a Catweasel drive and a normal HD drive, lift the pin as described above, but solder two fine wires, one for the pin's pad and another to the pin, leading off to a small toggle switch on the drive fascia. When the toggle switch is in the on position, the drive will function as a normal HD / DD drive, depending upon which type of disk you put in the drive. With the switch in the off position, the drive will function as only a DD drive, ideal for Catweasel. You will have to be extremely careful where you place your toggle switch, to avoid fouling the drive mechanism when a disk is inserted, triple check this, as the disks drop downwards after they are inserted.

If I haven't been clear enough in this post, I'll take some pictures for people.



Paul

[Arnie]

Seriously, wouldn`t it just be easier to put tape over the hole???

[Jope]

Preferably use DD disks to store DD bitstreams. :-)

You can still buy new DD disks online, also used ones.

[Allen1]

Hi there Loedown,

I don't have a Catweasel or a drive that could be converted to Amiga use but I would have thought that simply cutting a track leading to or away from the switch would be simpler, this would allow you to bridge the track via a switch wired to either side of the break and still be used for both types of disk as you mentioned in your post. The idea is a good one when you consider how often people are likely to forget to tape up the hole or the tape comes away and causes hassle (my only experience with that idea was video tapes though but I would expect the same problems to take place with disks)

All in all your idea is a very practical and simple solution to what would be a tedious job when a lot of disk copying is involved and you don't have the right disks for the job

[Loedown]

Originally Posted by Allen1

Hi there Loedown,

I don't have a Catweasel or a drive that could be converted to Amiga use but I would have thought that simply cutting a track leading to or away from the switch would be simpler, this would allow you to bridge the track via a switch wired to either side of the break and still be used for both types of disk as you mentioned in your post. The idea is a good one when you consider how often people are likely to forget to tape up the hole or the tape comes away and causes hassle (my only experience with that idea was video tapes though but I would expect the same problems to take place with disks)

All in all your idea is a very practical and simple solution to what would be a tedious job when a lot of disk copying is involved and you don't have the right disks for the job

Cutting a track is worthwhile, however it's a much neater job to simply lift a switch pad, which can then be used to go off to a switch, much cleaner than if you cut a track and decide later to reconnect, you either have to go the mod wire / via trick, or scrape back the solder resist...with my way, you bend the pin back down and solder.

I agree with everyone else about tape over the hole, but I know that HD disks are far easier to get and the Amiga isn't usually so fussy. I've seen everything about the magnetic domains, but meh, it works

Paul

[alexh]

I've used HD disks as DD and DD disks as HD for 10's of years and empirically they predominantly work well in both directions for long periods of time.

Anyone else like me drill holes in the majority of their Amiga disk collection so they could use them with their SNES copier?

[Jope]

I did that for all of my module disks when I bought a PC. Then I formatted them to high capacity with 2M. They didn't work very well.. ;-)

Your mileage may vary, but it's something to keep in mind.

[alexh]

SNES used 1.76Mbytes. Almost all of my disks were recycled coverdisks. A company in Blackpool used to recycle unsold computer magazines and all the disks were "thrown away" to re-appear in the local shops for 10p each.

This is an interesting mod but I've never successfully taken a floppy drive to pieces. Or more correctly I've never successfully put one back together.

[Loedown]

Originally Posted by alexh

SNES used 1.76Mbytes. Almost all of my disks were recycled coverdisks. A company in Blackpool used to recycle unsold computer magazines and all the disks were "thrown away" to re-appear in the local shops for 10p each.

This is an interesting mod but I've never successfully taken a floppy drive to pieces. Or more correctly I've never successfully put one back together.

Do you want some pictures?

[prowler]

Originally Posted by Loedown

Do you want some pictures?

I would definitely appreciate some, Paul!

[Loedown]

Hope that helps

[prowler]

Thanks for the pics, Paul!

All very self-explanatory. Great job!