• Please review our updated Terms and Rules here

Show us your Tandy Computers!

I guess I'll go ahead and drop a link to my latest video in here. Technically it features a Tandy 1000 HX, but those of a delicate constitution when it comes to keeping things original may want to avert their eyes. ;)


It was a really fun build; tedious in some places, but cobbling together a primitive wood case and re-encoding a surplus keyboard let me pretend I was participating in real Old Tyme Home Computing, Circa 1976.
 
This forum seriously needs a like button!

Great work with the franken-tandy too. I'm waiting to build a TL/2 based franken Tandy from bits I found cheap on eBay - it'll help me finish testing my internal floppy adapters to enhance their compatibility.
 
This forum seriously needs a like button!

Thanks! Like I said, it was really fun to make something like this, even if soldering that massive ratsnest on the back of the keyboard and diddling with the ribbon cable connectors gave me a few brief bouts of low-grade madness.

Great work with the franken-tandy too. I'm waiting to build a TL/2 based franken Tandy from bits I found cheap on eBay - it'll help me finish testing my internal floppy adapters to enhance their compatibility.

At least a TL/2 being able to use generic XT keyboards will save you that one little bit of fun. Or deprive you of it, depending on just how sick you are. ;)

I'm curious what the deal is with any sort of incompatibility it is you're seeing. Did Radio Shack change the pinouts at some point? It seemed to match up correctly to the service manual on my HX. (I do vaguely wonder if they weren't super careful at the factory and may have installed that weird Y-floppy cable backwards in some machines, with the colored pin 1 wire on the wrong side.)
 
An idea I had but discarded (for now) was trying to make an Osborne/Kaypro style portable out of it. I left enough leash on the keyboard ribbons specifically in case I try revisiting that. ;)

(I've been casually trying to determine if it's possible for any of those cheap multi-standard LCD panel driver boards you can get so cheaply from China to accept 15.7khz on their RGB ports. Since they do accept NTSC it seems at least it should be technically possible...)
 
Thanks! Like I said, it was really fun to make something like this, even if soldering that massive ratsnest on the back of the keyboard and diddling with the ribbon cable connectors gave me a few brief bouts of low-grade madness.

I bet! :D

At least a TL/2 being able to use generic XT keyboards will save you that one little bit of fun. Or deprive you of it, depending on just how sick you are. ;)

I'm curious what the deal is with any sort of incompatibility it is you're seeing. Did Radio Shack change the pinouts at some point? It seemed to match up correctly to the service manual on my HX. (I do vaguely wonder if they weren't super careful at the factory and may have installed that weird Y-floppy cable backwards in some machines, with the colored pin 1 wire on the wrong side.)

I'll use my XT keyboard - I dont feel like being a masochist on this one. :D

RatShack changed the FDD pins very slightly between the HX and newer units, eg on the HX pin 3 is 5v but this is NC on the TL, plus on the TL pins 29-33 had the 12v removed. That's about it really - I also wanted to test some other stuff with my TL/2 board.

I've definately had a handful of HX customers with the Y cable installed backward in HX's, bizarrely they still work but to use my adapters I have them snip off the key on the FDD center connector and install them backwards and they still work, NFI what's going on because I dont have a HX to play with.
 
An idea I had but discarded (for now) was trying to make an Osborne/Kaypro style portable out of it. I left enough leash on the keyboard ribbons specifically in case I try revisiting that. ;)

(I've been casually trying to determine if it's possible for any of those cheap multi-standard LCD panel driver boards you can get so cheaply from China to accept 15.7khz on their RGB ports. Since they do accept NTSC it seems at least it should be technically possible...)

Let us know if you find any that accept 15.7KHz on VGA, because from there, it's a simple circuit to convert the RGBi output into clear and readable 80-column 16-colour Tandy goodness!

The RCA jack works reasonably enough in 40-colum mode on a CRT, if you didn't have money for a monitor back in the day, but it looks like **** on an LCD.
 
Last edited:
Let us know if you find any that accept 15.7KHz on VGA, because from there, it's a simple circuit to convert the RGBi output into clear and readable 80-column 16-colour Tandy goodness!

Yeah, last time I went to the local electronics shop I bought the parts to slap together the circuit (the version that includes the brown fix). I figure I can test it on the 1084 in Analog mode and then, well, see what I can see.
 
I've definately had a handful of HX customers with the Y cable installed backward in HX's, bizarrely they still work but to use my adapters I have them snip off the key on the FDD center connector and install them backwards and they still work, NFI what's going on because I dont have a HX to play with.

That's odd that they couldn't just flip the cable end-for-end; was the hooded connector on the motherboard installed backwards (on my board at least it does have a key in the correct orientation), or did they just jam the cable in the wrong way at the factory, key be damned? Weird.
 
That's odd that they couldn't just flip the cable end-for-end; was the hooded connector on the motherboard installed backwards (on my board at least it does have a key in the correct orientation), or did they just jam the cable in the wrong way at the factory, key be damned? Weird.

The connector shroud is keyed so you shouldn't be able to install the Y cable in the wrong way - it's the key from the center connector that I've had ppl snip off to allow them to turn the cable around. The cable itself isn't actually weird (just clever) - I built a replica from customer photos and it works perfectly in my Amiga's.

The pinouts from the cable look like this on the "strange" HX's:

jnon7HH.jpg
 
The pinouts from the cable look like this on the "strange" HX's:

So... I guess I'm still not getting what's "different" about the cable; it looks to me like they just plugged the whole assembly in backwards, which would put the plastic key notch on the wrong side. IE, if you leave the highlights in the same place in the picture and rotate the end 180 degrees then the key peg will be on the "odd" side, and in that orientation it would match correctly with the orientation of the notch in the shroud on my HX's motherboard. (Pinouts.ru says the notch should be on the "odd" side, IE, facing down relative to the power pins in the orientation you're holding the cable, which again matches how my HX's motherboard connector is laid out.)

Did any of the people with this problem detach the cable from the motherboard and verify that the motherboard actually has a notched shroud and *it* has the notch on the wrong side? Or, alternatively, did they check and find that the IDC connector in the center of their cables is rotated 180 degrees from the connectors on the end? Maybe Radio Shack just ditched the shroud on the motherboard connector and the assemblers started putting the cables in in random orientations.
 
So... I guess I'm still not getting what's "different" about the cable; it looks to me like they just plugged the whole assembly in backwards, which would put the plastic key notch on the wrong side. IE, if you leave the highlights in the same place in the picture and rotate the end 180 degrees then the key peg will be on the "odd" side, and in that orientation it would match correctly with the orientation of the notch in the shroud on my HX's motherboard. (Pinouts.ru says the notch should be on the "odd" side, IE, facing down relative to the power pins in the orientation you're holding the cable, which again matches how my HX's motherboard connector is laid out.)

Did any of the people with this problem detach the cable from the motherboard and verify that the motherboard actually has a notched shroud and *it* has the notch on the wrong side? Or, alternatively, did they check and find that the IDC connector in the center of their cables is rotated 180 degrees from the connectors on the end? Maybe Radio Shack just ditched the shroud on the motherboard connector and the assemblers started putting the cables in in random orientations.

Exactly, it looks like it's in backward but the keyed shroud should prevent this - these units definitely have a keyed shroud, it's the first thing I get folks to check. The second thing I get them to do is remove the key from the middle connector and reverse the cable and then everything works. It's a real head-scratcher. :confused:
 
It's backwards on my HX too. I think this is just because the drives the HX's used had the keyway on the opposite side of what we would now call "standard."

HX floppy.jpg

Tandy was using Shugart drives at least until the end of the 1000 line, and the PC "standard" was still in flux in 1987. By the RSX, they at least had the key the right way around, though you still needed to swap pins 10/12 if you wanted to use a regular floppy in place of the factory installed floppy (I had to replace mine).
 
Last edited:
It's backwards on my HX too. I think this is just because the drives the HX's used had the keyway on the opposite side of what we would now call "standard."

View attachment 57421

Tandy was using Shugart drives at least until the end of the 1000 line, and the PC "standard" was still in flux in 1987. By the RSX, they at least had the key the right way around, though you still needed to swap pins 10/12 if you wanted to use a regular floppy in place of the factory installed floppy (I had to replace mine).

It's very odd that some are configured like this and others aren't - I'd never bothered looking at that section of the Tech manual before but you are correct that the notch is in the "wrong" place on the drive. Any chance you could post a couple of high res pics of the cable removed from your HX?

This is a copy I made of a customer cable that had died.

IMG_2044.jpg

IMG_2040.jpg
 
So that cable in the picture definitely seems to have the key notch on the "wrong" side compared to the stripe, which is usually supposed to indicate pin one, at least if you plugged it into my HX motherboard. It *would* put the cable in the correct orientation if you were matching up with a floppy drive that had the notch on the "wrong" side.

I do remember there being some inconsistancy with that keying, or whether it was even present at all. I have a floppy drive in the junk box that doesn't have a plastic shroud around the pins to enforce key orientation, but it does have a breakout-able notch on the circuit board for what would be the "correct" orientation today that never got the removable chunk knocked out, and many of my floppy cables don't have it...

Which is why the stripe should indicate pin 1. Consistantly. :p
 
So that cable in the picture definitely seems to have the key notch on the "wrong" side compared to the stripe, which is usually supposed to indicate pin one, at least if you plugged it into my HX motherboard. It *would* put the cable in the correct orientation if you were matching up with a floppy drive that had the notch on the "wrong" side.

I do remember there being some inconsistancy with that keying, or whether it was even present at all. I have a floppy drive in the junk box that doesn't have a plastic shroud around the pins to enforce key orientation, but it does have a breakout-able notch on the circuit board for what would be the "correct" orientation today that never got the removable chunk knocked out, and many of my floppy cables don't have it...

Which is why the stripe should indicate pin 1. Consistantly. :p

That cable is designed to connect to the mainboard via the center connector - I plugged it into my Amiga 1200 (also uses shugart) the "right way" and was able to drive a pair of goteks without issue.
 
That cable is designed to connect to the mainboard via the center connector - I plugged it into my Amiga 1200 (also uses shugart) the "right way" and was able to drive a pair of goteks without issue.

I looked up a picture of the Amiga 1200 motherboard and the ones I saw didn't seem to have a shroud around the pins.

Anyway, what's "wrong" with that cable from a conventional standpoint is simply the fact that the keys are not all oriented the same relative to the wire. The middle one is flipped in such a way that it *would* put the colored pin at the wrong end of the connector. Here's a picture I took of my HX's motherboard connector with my ad-hoc adapter:

close-up.jpg

That cable I have plugged in there has little red spots instead of a clear stripe, but you can see the marked side and the "low" pins (the five 5v ones and the NC pin 0) are to the left of the notch in the connector hood. (IE, the notch on the motherboard connector is on the "Odd" side, like it is in the PC convention.) If we connected the center connector in that cable in your picture so the notch matched then the striped end would be over the three 12v pins to the right of the notch. Alternatively, if we plugged in either end connector then the stripe *would* be at the pin 1 position. That they're not consistent about key vs color orientation is *bad* and, worse, as this cable is laid out if you matched the center key to the motherboard and plugged a floppy into either end while observing the cable color *or* the "standard" (not tandy) notch orientation it'll be backwards to what it's supposed to be.

If Tandy really wanted it to be like this they should have put the shroud on the motherboard backwards to match the drives. :b
 
My A1200 doesn't have a shroud but it does have pin 1 marked quite clearly. When I installed it I did have the red wire up that end but never bothered checking to see which pin was actually pin 1. One good thing about testing on my Amiga's they dont have power in the cable to let the magic smoke out. :D

Hmmm, it looks like I really should make an HX specific adapter range. I'm glad I pulled them until I could get to the bottom of the issues.
 
It's very odd that some are configured like this and others aren't - I'd never bothered looking at that section of the Tech manual before but you are correct that the notch is in the "wrong" place on the drive. Any chance you could post a couple of high res pics of the cable removed from your HX?

This is a copy I made of a customer cable that had died.

View attachment 57428

View attachment 57429

May as well. I wanted to take it apart and clean the disk heads anyways. Probably ought to find myself a 3.5" cleaning disk.

IMG_20191121_172324927.jpgIMG_20191121_172627914.jpg

IMG_20191121_172751554 - crop.jpg
Pretty much the same, only the stock cable is 14" instead of 17".
 
Back
Top