3.5" Drive on a TI99/4a?

[Tempest]

How do you hook up a 3.5" drive to a TI99/4a? I know it's possible as I've seen pictures of PEB's with them. I'd like to try and do this so I can transfer files from my PC to my TI. I know there's a program that lets you write files in the TI99 format on the PC so I think this would be possible.

 

Tempest

[carmel_andrews]

if the TI99 comes with an edge connector (like the PBI/ECI from the A8) you could hack yourself a floppyboard device which should allow you to use a 3.5' disk mech, essentially making a 3.5' drive

 

All you need then is a DOS that works with a 3.5' drive and supports higher densities

[TI99Kitty]

How do you hook up a 3.5" drive to a TI99/4a? I know it's possible as I've seen pictures of PEB's with them. I'd like to try and do this so I can transfer files from my PC to my TI. I know there's a program that lets you write files in the TI99 format on the PC so I think this would be possible.

 

Tempest

 

Tex*In Treasures offers a 3.5-inch floppy drive that's already configured for the TI.

[Tempest]

I see that, but I already have a drive (that exact same one actually). What did they have to do to 'configure' it?

 

EDIT: Ahh now THIS is what I'd like to do: http://www.mainbyte.com/ti99/2drives/2drives.html

 

Tempest

[Tursi]

We had a long debate about this on the TI list not long ago, which led to me finally putting a 3.5" drive on mine.

 

I saved the notes here: http://harmlesslion.com/text/ti_35_inch_floppy.txt

 

But it's short, so to copy the article:

 

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).

 

Using a HD drive on the TI Controller with HD disks /really/ confuses the machine... it's goes beyond simply not working to seriously misbehaving. I "converted" my HD 3.5" drive by using a bit of solder to permanently disable the HD hole sensor.

Edited January 19, 2010 by Tursi

[Tempest]

Are there any restrictions on the type of drive that can be used or are all drives ok?

 

Tempest

[Opry99er]

Watch my YouTube video on configuring 2 3.5s on my TI as DSK2 and DSK3, keeping my 5.25 as my DSK1. I use a standard TI disk controller and a standard TI 5.25. Check out "Opry99er" on YouTube. Hope this helps.

[rocky007]

Watch my YouTube video on configuring 2 3.5s on my TI as DSK2 and DSK3, keeping my 5.25 as my DSK1. I use a standard TI disk controller and a standard TI 5.25. Check out "Opry99er" on YouTube. Hope this helps.

 

 

hi opry99er, i checked your video, but did'nt understood very well... you simply connected the 3"1/2 on the disk controller, without upgrade of the disk controller card ?

[Opry99er]

The TI controller card handles 3.5 drives just fine. No mods needed.

[Tursi]

I used a standard 1.44MB 3.5" floppy drive. But if I inserted a 1.44MB floppy disk in that state, my controller card itself malfunctioned. To avoid that problem, either exclusively used 720k floppies only, or disable the HD sensor in the drive (this is what I did) so that it thinks all floppies are 720k.

[S1500]

Interesting. I have a spare 3.5 inch drive so I might have to try this.

 

For those who don't have a half-height 5.25 drive, is it not too hard to fandangle cables to work outside of the PEB?

[Tursi]

If you have a long enough cable. Just remember you can't use a PC cable with the half-twist in it - you either need to remove the twist or get a cable that doesn't have it.

[RXB]

If you have a long enough cable. Just remember you can't use a PC cable with the half-twist in it - you either need to remove the twist or get a cable that doesn't have it.

 

 

90% of the connectors are plastic, so if you are carefull you pry up the outside connector sections and the clamp comes up off the plug. Flip the cable over and put it back together.

 

If you look at the connectors you can see the snaps on the outside of the connectors, use a small screw driver to help you get a fingernail under it and you are set to go.