Changing my drive configuration

[Opry99er]

Greetings.

 

I've decided to basically terminate the use of my 5.25" drive altogether. It is the only internal drive I have, and I do not ever use it, due to its reliability issues and the flakiness of the media.

 

I've been transferring a ton of stuff over to 3.5" diskettes, and most of the XB programs require the main disk be in DSK1 in order to load, read, write, etc. This is problematic, as my 3.5 drives are #2 and #3.

 

I tried to disconnect my internal drive, hoping the controller card would read the first external drive as DSK1, but it did not work. I then started looking at what it would take to get the externals set up to DSK1 and DSK2, leaving the 5.25" as basically a space-filler for the time being. Looking at my cable ends, I do not have the correct cables to set up the external drive as DSK1, due to the fact that the cable exiting my 3.5" drive housing has a card-edge connector, designed to fit on the back of the FDC. The internal cable that was connected to the 5.25 drive also has a card-edge type connection, as that is how the 5.25 hooks up. Of course, the 3.5" drives have a standard 34 pin floppy connector.

 

What would I need to do to get this set up to run my 3.5s as DSK1 and DSK2? The termination won't need to be changed, as DSK3 will become DSK2 and that will be all the drives I need for the time being. Is there no way to modify the FDC to accept ONLY card-edge drives and register them as #1 and #2 instead of #2 and #3?

 

Just curious...

[Opry99er]

I read in the manual that the external drives are set to 2 and 3, but there was some discussion on this subject a while back as it pertained to the HxC... I guess I am reading conflicting info.

 

Is it as simple as changing jumpers on my 3.5" drives??

Edited July 27, 2016 by Opry99er

[+Ksarul]

It really depends on the drive. Some drives have jumpers installed to allow switching the drive's number in the chain. Others require that the appropriate drive select wire in the cable is moved to the position that the drive is expecting as the drive select input (thus using your cable as the jumper). It really depends on what is in your box.

[+arcadeshopper]

The 3.5in drives have either a jumper to do drive select or there are soldered connections on drive select locations

 

Sent from my LG-H811 using Tapatalk

[+Schmitzi]

Which 3.5"-drive are you using ? Maybe I have infos about a mod

 

But the easiest way may be to connect it inside the PEB, at the end of the cable,

and to swap some wires before this last connector.

 

As the next-to-last last connector stays "unswapped/undrilled", you could connect another jumperable drive there, too

 

here just an info from another thread I think, but has to be discussed as I don´t know at all:

(I think wire 10 and 12 have to be swapped, but not for sure!)

 

[Opry99er]

Thanks for the info fellas.

 

 

 

Mitsumi D359M3D is the model. Looking up schematics online now.

 

 

The best solution may be to just get a 3.5 for the internal drive... Save having to make a bunch of mods.

[Opry99er]

Found some info... looks like this may be possible with a pin-select option on the cable.... Researching...

Edited July 27, 2016 by Opry99er

[Opry99er]

 

Using a 3.5" Floppy Drive on the TI-99/4A
-----------------------------------------

Contributions by Marc Hull, Jon Vogel, and Tony Knerr.

1) Use a straight cable - no twists.

2) Change the drive select line ON THE CABLE in the appropriate place.
Pin 10 is DSK1, pin 12 is DSK2, and pin 14 is DSK3. The appropriate lead
goes to pin 12 on the floppy drive. With no changes, a standard 3.5"
drive will be DSK2.

3) Mix and match whatever you want, if you've got mixed 5.25's and 3.5's,
remove the termination packs from the 5.25's.

4) The HFDC doesn't like too much termination, other cards simply don't care.

5) Use only double density 3.5" disks unless you've got a Geneve and
are using high density. Taping over the hole on high density disks is
NOT RELIABLE, period.

6) Don't use a HD diskette on non-Geneve-HD systems - doing so can confuse
the controller. If you have an HD drive, you might want to disable the HD
sensor so that it never sees the hole. Doing so and using HD floppies
anyway is taking reliability into your own hands (see #5).

Edited July 27, 2016 by Opry99er

[Shift838]

Greetings.

 

I've decided to basically terminate the use of my 5.25" drive altogether. It is the only internal drive I have, and I do not ever use it, due to its reliability issues and the flakiness of the media.

 

I've been transferring a ton of stuff over to 3.5" diskettes, and most of the XB programs require the main disk be in DSK1 in order to load, read, write, etc. This is problematic, as my 3.5 drives are #2 and #3.

 

I tried to disconnect my internal drive, hoping the controller card would read the first external drive as DSK1, but it did not work. I then started looking at what it would take to get the externals set up to DSK1 and DSK2, leaving the 5.25" as basically a space-filler for the time being. Looking at my cable ends, I do not have the correct cables to set up the external drive as DSK1, due to the fact that the cable exiting my 3.5" drive housing has a card-edge connector, designed to fit on the back of the FDC. The internal cable that was connected to the 5.25 drive also has a card-edge type connection, as that is how the 5.25 hooks up. Of course, the 3.5" drives have a standard 34 pin floppy connector.

 

What would I need to do to get this set up to run my 3.5s as DSK1 and DSK2? The termination won't need to be changed, as DSK3 will become DSK2 and that will be all the drives I need for the time being. Is there no way to modify the FDC to accept ONLY card-edge drives and register them as #1 and #2 instead of #2 and #3?

 

Just curious...

 

I have done this many times in my PEBs and did this for others as well.

 

So a straight though cable will recognize on a newer 3.5 drive with no drive select switch as DSK2.

 

I have made cables that have DSk1 and 2.

 

On one of the connectors you will need to swap the drive select lines. move the wire from pin 10 to pin 12 and then the wire from pin 12 to pin 10. Now you have DSK1.

 

I got the info years ago and now it's HERE