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What's the best way to get an external FDD onto a Tandy 1000?

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Load"*"81

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This is my first genuine foray into vintage computer hardware, excluding game consoles. I found a Tandy 1000 SL at a Goodwill yesterday and couldn't help but snatch it up. It came with a CGA monitor and a dot matrix printer (I'm not at home right now, so I couldn't tell you what the printer's model number is, but it has both a Centronics parallel port and a DIN port in the back). The computer and monitor work beautifully; it boots right up into DOS 3/DeskMate, and I was pleasantly surprised to see that the RAM had already been upgraded to 640k.

Unfortunately, it didn't come with any disks, and being an SL it only has the one 5.25" drive. On top of that, I haven't been able to test the printer, because it didn't come with a parallel cable -- and I have no idea where to even look for a cable that attaches to that 34-pin card-edge port on the back of the computer.

The printer is only a secondary issue, though. I really just want to be able to attach an external 3.5" diskette drive, and I don't know much about where to start. Surfing around, I've seen many people suggest the Mircosolutions Backpack diskette drive (there are a baker's dozen of them available on Ebay right now, so at least they aren't hard to find), but since the SL doesn't have a standard DB-25 parallel port, and I think I can safely assume the drive won't come with Tandy's 34-pin card edge connector, how do I go about attaching it to the computer and getting it up and running?

Barring that, are there any other options -- any other 3.5" external FDDs for the Tandy 1000 that I'm not aware of? I know that there was a TRS-80 diskette drive that used the serial port, but would that even work with the Tandy 1000? Or do I just have to bite the bullet and pop for an HxC?
 
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Cool, thanks! I'll bet the ISA card is probably the easiest route to take, assuming I can track one down.

Are there any driver issues you're aware of that I should know about?
 
It should literally be Plug & play. I have used one in the past with a parellel port ZIP drive and had no issues at all. Only thing is you may have to get into the BIOS to disable the on board parellel port. Check that website for 1000SL documentation. I never owned a 1000 sl so not sure about the BIOS thing.
 
Load"*" said:
The printer is only a secondary issue, though. I really just want to be able to attach an external 3.5" diskette drive, and I don't know much about where to start. Surfing around, I've seen many people suggest the Mircosolutions Backpack diskette drive (there are a baker's dozen of them available on Ebay right now, so at least they aren't hard to find), but since the SL doesn't have a standard DB-25 parallel port, and I think I can safely assume the drive won't come with Tandy's 34-pin card edge connector, how do I go about attaching it to the computer and getting it up and running?

Barring that, are there any other options -- any other 3.5" external FDDs for the Tandy 1000 that I'm not aware of? I know that there was a TRS-80 diskette drive that used the serial port, but would that even work with the Tandy 1000? Or do I just have to bite the bullet and pop for an HxC?
Click to expand...

Load"*" said:
Cool, thanks! I'll bet the ISA card is probably the easiest route to take, assuming I can track one down.

Are there any driver issues you're aware of that I should know about?
Click to expand...

The Backpack drives are the best bets for attaching an external floppy drive. Tandy 1000s will not use TRS-80 serial floppy drives. However, as indicated below, you will need a parallel port ISA card for it to work with the Tandy 1000SL. I believe you can disable the card edge parallel port using the setup program. Moreover, you will need some way to load the Backpack floppy's driver because the system will not recognize the drive without one. It is better to connect an internal 3.5" 1.44MB drive, used in 720KB mode.
 
Are you sure? I'm pretty sure there is no way to disable the on-board parallel port. Back in the day, I got a short in the $30 (or so) Tandy special printer cable...did the math and found it was cheaper to add an expansion card and buy a standard cable than to buy another Tandy cable. I played games with a utility to swap LPT1 and LPT2 so I wouldn't have to tell everything to print to LPT2...would have thought I would have noticed and used the utility to disable the port rather than do that...but perhaps I just missed it!

Wesley
 
Load"*" said:
I really just want to be able to attach an external 3.5" diskette drive,
Click to expand...

Why not an internal drive? Any standard 3.5" 1.44 MB drive will work -- it will only read and write 720K disks using the built-in controller, but that's good enough for an XT class machine.

Just be aware that the 1000SL supplies power through the floppy drive cable. The Tandy-supplied cable has cutouts to prevent this power from reaching the floppy drives, but if you replace the cable (as you'll probably need to, because the factory supplied cable is too short to reach anything other than the original 5.25" TEAC drives), you can modify it as described here:

http://www.oldskool.org/guides/tvdog/1kfaq.html#II.C.2
 
vwestlife said:
Why not an internal drive? Any standard 3.5" 1.44 MB drive will work -- it will only read and write 720K disks using the built-in controller, but that's good enough for an XT class machine.

Just be aware that the 1000SL supplies power through the floppy drive cable. The Tandy-supplied cable has cutouts to prevent this power from reaching the floppy drives, but if you replace the cable (as you'll probably need to, because the factory supplied cable is too short to reach anything other than the original 5.25" TEAC drives), you can modify it as described here:

http://www.oldskool.org/guides/tvdog/1kfaq.html#II.C.2
Click to expand...

Now, see, that FAQ doesn't mention that the SL is one of the models that draws power through the cable. "The HX, TX, SL/2, TL's, RL's, RLX's, and RSX's use a special floppy drive that draws power through the data cable."

Are we sure about this? It's one of the main reasons I'd prefer to get an external drive working.

EDIT: A bit lower down, "The following systems use special 3-1/2" 720k floppy drives that draw power through the data cable: 1000HX, RL's, RLX's, RSX's, SL/2 (drive A: only), TL's, and TX. You must replace those drives with another Tandy-style drive. ... The original 1000, A, HD, EX, SX, and SL use standard 360k floppy drives." (Which, I guess, is referring to the 5.25" drive, but still, what's going on here?)

So, assuming I get a standard 3.5" 1.44 MB FDD (easily done), and it'll probably come with a standard cable with a middle untwisted "B:" connection and an end twisted "A:" connection, how would I plug this sucker into my Tandy 1000SL, ideally in such a way that the new 3.5" FDD can be the A: drive and the old 5.25" FDD already in there can be the B: drive?
 
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The best reference is the Tandy 1000 Notes & Jumpers Manual:

ftp://ftp.oldskool.org/pub/tvdog/tandy1000/documents/1ktech-1.zip

The 1000SL is on page 130.

When I added a 3.5" drive to my 1000SL, I kept the original Tandy floppy cable with the holes in it, so the power being supplied to the cable was not a problem because the Tandy cable has holes punched in it to block the power from going through.

I was lucky that I had a card edge-to-pin type connector adapter that was long enough that I could still use the Tandy cable even though it's very short and normally can't reach a 3.5" drive.

The Tandy cable does not use the twist between the A and B drives. Instead, you have to jumper drive A as Drive Select 0 (DS0) and drive B as Drive Select 1 (DS1).

Since newer 3.5" drives are hard-wired to DS1 and don't let you change it, I used the option in SETUPSL to swap the floppy drive letters, making the computer recognize it as drive A even though it's jumpered as drive B (DS1).
 
Load"*" said:
Now, see, that FAQ doesn't mention that the SL is one of the models that draws power through the cable. "The HX, TX, SL/2, TL's, RL's, RLX's, and RSX's use a special floppy drive that draws power through the data cable."

Are we sure about this? It's one of the main reasons I'd prefer to get an external drive working.

EDIT: A bit lower down, "The following systems use special 3-1/2" 720k floppy drives that draw power through the data cable: 1000HX, RL's, RLX's, RSX's, SL/2 (drive A: only), TL's, and TX. You must replace those drives with another Tandy-style drive. ... The original 1000, A, HD, EX, SX, and SL use standard 360k floppy drives." (Which, I guess, is referring to the 5.25" drive, but still, what's going on here?)

So, assuming I get a standard 3.5" 1.44 MB FDD (easily done), and it'll probably come with a standard cable with a middle untwisted "B:" connection and an end twisted "A:" connection, how would I plug this sucker into my Tandy 1000SL, ideally in such a way that the new 3.5" FDD can be the A: drive and the old 5.25" FDD already in there can be the B: drive?
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IBM PC-compatible 5.25" 360KB Double Density drives never supported power through a drive cable, they will always have a 4-pin Molex plug for power. Tandy 1000 5.25" drives always used a Molex connector. I am also unaware of any 5.52" 1.2MB High Density drives that don't have a Molex connector either. By contrast, it is hard to find a 3.5" 720KB Double Density drive that has a mini-Molex connector for power.

Tandy was ahead of its time in allowing users to select which drive would be Drive A: and which would be Drive B: They way they did this was to use a wholly untwisted drive cable. So if you take the standard universal 34-pin floppy drive cable with 3 pin-header connectors and 2 card edge connectors, untwist the twist between the connectors for Drive A: and Drive B:. You very well need to buy new connectors for the ones you need to remove, but they are pretty cheap.

The available material on the SL is conflicting on whether it supplies power through the drive cable. If you want to be 100% safe regarding the power through the drive cable on the SL, cut small holes in the wires corresponding to pins 3, 5, 7, 9, 11, 29, 31, 33 before you get to the drive connectors. That is what Tandy did on its cables and that will save your drives from this issue.
 
BTW, one downside to having both 5.25" and 3.5" floppy drives installed in a 1000SL is that it leaves no free drive bays for a hard drive. Tandy's preferred option was to sell you a hard-card (a 20 or 40 MB IDE-XT drive bolted to a ISA card frame containing a Seagate ST-05X interface card). But if you don't have one of those, this computer is an ideal candidate for an XT-IDE or XT-CF card.
 
vwestlife said:
BTW, one downside to having both 5.25" and 3.5" floppy drives installed in a 1000SL is that it leaves no free drive bays for a hard drive. Tandy's preferred option was to sell you a hard-card (a 20 or 40 MB IDE-XT drive bolted to a ISA card frame containing a Seagate ST-05X interface card). But if you don't have one of those, this computer is an ideal candidate for an XT-IDE or XT-CF card.
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Only true if you go with a MFM type HD. May be time for the XT-IDE controller to come into play. Fifty cents' worth of scrap metal and you can make a bracket and suspend the IDE from the numerous places within the chassis. I can post a picture of the IDE in my SX, which is similar. BTW, the 3.5 & 5.25 drives coexist perfectly in my SX, should be the same in the SL.
 
Okay, well, opening up the case, there's already a hard drive installed in there. Pretty awesome. And the 5.25" floppy drive does indeed have the hole-punched cables and a separate molex connector for power; but it only has another card-edge connector in the middle of the floppy data cable, so I'm going to have to replace that.

It looks like I'm going to have to get one of those five-connector cables with both card-edge and pin connectors on it and modify it by clipping all those ground lines, eh? But am I going to have to find some way to "un-twist" the cable twist that's normally there for the second drive?
 
Great Hierophant said:
Untwisting the twist is really easy.
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Okey doke. And just to make sure, then, I have to do the following:

1) Get a five-connector cable and modify it by (a) untwisting the swapped control lines and (b) cutting all those ground lines between the control/mobo and middle connectors, to make it like a Tandy cable.

2) The 5.25" drive already in the machine is already jumpered for A:, while any 3.5" drive I find is likely to be hard-wired as B:, so I should be able to simply connect them both to the floppy ribbon, the old 5.25" drive to the card-edge connector near the end of the cable and the new 3.5" drive to the pin connector in the middle of the cable.

3) Configure Setup to make sure that the BIOS recognizes the new drive, and (since I want the new drive to be A: ) switch the drive letters.

Is that pretty much it?
 
Load"*" said:
Okey doke. And just to make sure, then, I have to do the following:

1) Get a five-connector cable and modify it by (a) untwisting the swapped control lines and (b) cutting all those ground lines between the control/mobo and middle connectors, to make it like a Tandy cable.

2) The 5.25" drive already in the machine is already jumpered for A:, while any 3.5" drive I find is likely to be hard-wired as B:, so I should be able to simply connect them both to the floppy ribbon, the old 5.25" drive to the card-edge connector near the end of the cable and the new 3.5" drive to the pin connector in the middle of the cable.

3) Configure Setup to make sure that the BIOS recognizes the new drive, and (since I want the new drive to be A: ) switch the drive letters.

Is that pretty much it?
Click to expand...

Any fairly new 3.5" floppy is likely to be strapped to DS0 or "A". I did manage to find one that let me un-solder a jumper on the its PCB and set it up as DS1 (Harry Schwartz brand). You can easily hard select "A" or "B" on your Tandy 5.25" floppy. Either way, you can manipulate the the drive assignments through DOS upon boot.
 
Load"*" said:
Okey doke. And just to make sure, then, I have to do the following:

1) Get a five-connector cable and modify it by (a) untwisting the swapped control lines and (b) cutting all those ground lines between the control/mobo and middle connectors, to make it like a Tandy cable.

2) The 5.25" drive already in the machine is already jumpered for A:, while any 3.5" drive I find is likely to be hard-wired as B:, so I should be able to simply connect them both to the floppy ribbon, the old 5.25" drive to the card-edge connector near the end of the cable and the new 3.5" drive to the pin connector in the middle of the cable.

3) Configure Setup to make sure that the BIOS recognizes the new drive, and (since I want the new drive to be A: ) switch the drive letters.

Is that pretty much it?
Click to expand...

Exactly! :) Cable and jumper the 5.25" drive as A: (DS0) and the 3.5" drive as B: (DS1), and then go into SETUPSL /A and turn on the option to swap the floppy drive letters. And if you ever need to boot from a 5.25" disk, you can then un-swap the drives.
 
And one more question, again just to be certain, will the standard 3.5" drive be drawing its power through the data cable then? Or will I have to attach the 4-pin mini molex to the power supply?
 
Load"*" said:
And one more question, again just to be certain, will the standard 3.5" drive be drawing its power through the data cable then? Or will I have to attach the 4-pin mini molex to the power supply?
Click to expand...

As far as I know, the SL/2 draws through the cable. Your SL should use the standard Molex connector . Be assured that if my assessment is in error, it will be promptly correct here in this thread. :p
 
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