exxos's Atari, Amiga & retro forum

It's difficult to answer as it's impossible for me.to test every drive in the world to know.

The main problem is the HD select wire as I don't know where to solder on every drive, or if it will work,.some drives may not even have a switch. There's to many variables which is why I only state in using the MPF920 drives. It's a well known and documented drive.

In theory if you force 720k mode or 1.44 mode then you don't need the wire at all. But you lose automatic switching between DD and HD then.

exxos wrote: 08 Feb 2025 09:57 It's difficult to answer as it's impossible for me.to test every drive in the world to know.

The main problem is the HD select wire as I don't know where to solder on every drive, or if it will work,.some drives may not even have a switch. There's to many variables which is why I only state in using the MPF920 drives. It's a well known and documented drive.

In theory if you force 720k mode or 1.44 mode then you don't need the wire at all. But you lose automatic switching between DD and HD then.

I was just curious, since the TT, Mega STe and Falcon came with 1.44 HD drives.

Thanks Chris. :)

Toying around with a 2nd Exxos 1.44 HD kit that I got off Ebay (un-assembled).

So just making sure, if it will boot up and recognize a standard 720k floppy,
or boot up with a 1.44 HD floppy and recognize it, but not recognize any
floppy disk changes, it's most likely the white wire that runs from the mod
to the 1.44 HD floppy itself?

Is there anything else that could cause that kind of behavior? Thanks much.

Another quick question...

The " 0 " resistor that has to be moved on the 1.44 HD floppy drive - since it's a " 0 ",
if need be, could you just solder a bodge wire across that or even a solder blob?

(the SEL1/SEL0 connection)

Thanks!

Darklord wrote: 27 Jun 2025 19:14 Toying around with a 2nd Exxos 1.44 HD kit that I got off Ebay (un-assembled).

But what version ?

So just making sure, if it will boot up and recognize a standard 720k floppy,
or boot up with a 1.44 HD floppy and recognize it, but not recognize any
floppy disk changes, it's most likely the white wire that runs from the mod
to the 1.44 HD floppy itself?

Is there anything else that could cause that kind of behavior? Thanks much.

The wire to the drive is the HD select wire.

Disk change is done by a solder blob on later boards.. But you have to press ESC to refresh the window. Older TOS versions like below 104 probably won't work right anyway.

Darklord wrote: 27 Jun 2025 19:16 The " 0 " resistor that has to be moved on the 1.44 HD floppy drive - since it's a " 0 ",
if need be, could you just solder a bodge wire across that or even a solder blob?

Yes..

Jumpers are shown here... Solder blob will do the same job. Just be careful as the PCBs warp easily.

https://exxosforum.co.uk/atari/last/drive-mod/main.htm

You may want to look at the info on the install page as it lists all this info already.

https://exxosforum.co.uk/atari/last/floppy/index.htm

exxos wrote: 27 Jun 2025 19:22
But what version ?

The wire to the drive is the HD select wire.

Disk change is done by a solder blob on later boards.. But you have to press ESC to refresh the window. Older TOS versions like below 104 probably won't work right anyway.

It appears to be version 7, like the one I bought before.

If I boot the machine up with a 720k floppy inserted, it shows it correctly. No problems.

If I boot the machine up with a 1.44 HD floppy inserted, it shows it correctly. No problems.

If I boot up with either one and change the floppy to the other one, then double-click on
the Drive A icon, it won't read it.

If I boot up with either one and have the floppy drive window open on the desktop, change
the floppy out to the other one and hit "ESC", it won't read it. It attempts to keep showing the
contents of the original floppy.

I'm using TOS v3.06 so that's not an issue.

Thanks.

exxos wrote: 27 Jun 2025 19:24

Darklord wrote: 27 Jun 2025 19:16 The " 0 " resistor that has to be moved on the 1.44 HD floppy drive - since it's a " 0 ",
if need be, could you just solder a bodge wire across that or even a solder blob?

Yes..

Jumpers are shown here... Solder blob will do the same job. Just be careful as the PCBs warp easily.

https://exxosforum.co.uk/atari/last/drive-mod/main.htm

You may want to look at the info on the install page as it lists all this info already.

https://exxosforum.co.uk/atari/last/floppy/index.htm

Okay, thanks. :)

@Darklord Do you have the MCF jumpered on the PCB in front of the WD1772 on the floppy mod board ? Its the "trick" used to get TOS to re-read the floppy contents.

But I don't know if that trick works in TOS306. IIRC Atari might have changed how media detection works each TOS version.. But also , if your running PAK 306 TOS, that could be a whole other can of worms.

I found this program in Floppyshop, but no idea if it will work at all. I would have thought 306 would have fixed the MC issues anyway.

Hmm, not really sure what you're talking about? I don't recall any jumpers on the board, sorry.

For a system using only floppy drive A as the 1.44 HD drive and no drive B at all, do any of these
pad(s) need to be soldered together?


Thanks much.