Wednesday, May 24, 2017


Yesterday, I posted about some ideas for upgrades to the Tandy 1000 SX that I have on its way. The two most obvious ones are the NEC V20 CPU and the 8087 math co-processor.

Back in the day, Intel's 80x86 CPU line did not include a built in math co-processor. You had to purchase and install one separately all the way up through the 486DX if you wanted floating-point operations. Not a lot of software took advantage of this, and I never installed one back in the day. Even my Pentium-class machine was a Cyrix 686, which was slower than Intel's CPUs at floating point but faster in other areas. But it's something I had always wanted in my Tandy 1000 SX back then, and they're fairly inexpensive on eBay, so why not?

The other upgrade, which I hadn't done to my Tandy but had done to another, generic, XT-compatible machine, that I plan on is to swap the processor with an NEC V20. It is pin-compatible with the Intel 8088 but will give you a little more speed at the same clock rate. (The XT-class machine I had one in also had a crystal hack done, which also provided a little bit of speed boost.)

Tuesday, May 23, 2017


After I get my Tandy 1000SX set up, here are some upgrades I'm considering to make it more useful:

I have a CGA to VGA adapter already that was in an arcade cabinet, but which is not in use, but I may need a different one as the board I have doesn't support the intensity line, but, IIRC the CGA standard and, by extension, the Tandy graphics, requires it to get 16 colors. Without it, I believe only 8 colors will display.

Since it has dual 5.25" 360K floppies, I'll likely remove one and replace it with a 3.5" 720K floppy, or, more likely, floppy emulator. I can then put the removed 5.25" floppy in a desktop and give myself a way to create floppy disks.

There is no hard drive, so I will likely add an XT-IDE interface with a Compact Flash adapter. I always hated swapping floppies, so this, or at least the above floppy emulator, is a must for mass storage.

An 8-bit network card. Intel made an 8/16 model that is still reasonably priced on eBay. I could probably get away without the XT-IDE if I had networking, as I could mount a network share.

A Sound Blaster Pro. I like Tandy's built-in sound much better than a standard PC, but, I prefer a sound card. And even though the SBpro is a 16-bit card, plugging it in to an 8-bit slot will still work as long as I don't try to use a DMA channel that's only available via a 16-bit slot. The SBpro also has a header on it that will take a speaker connector for input, allowing me to pipe the Tandy sound through it to external speakers. This gives me the best of both worlds when it comes to sound.

The SX I purchased appears to have a modem and serial card in it, so neither of those should be necessary. Since I would like to add a standard parallel port, I may replace the serial card with either a serial/parallel or a serial/parallel/game card, especially if I don't add the SBpro above. I'm not sure if you can use the joystick port from either without conflicting with the onboard proprietary ports or not, but, if so, I wouldn't hesitate to try. If I forgo the SBpro, if I get a parallel card, I can build a generic version of a Covox Speech Thing. IIRC I had built one back in the day, but can't remember which machine I had it connected to.

Last but not least, I'm considering a VGA card. Obviously it's better graphics that TGA, but I'm a bit torn on this one. Part of the charm of the Tandy 1000 line is the Tandy-specific graphics and sound modes.

Monday, May 22, 2017

Tandy Keyboards

Tandy keyboards are a bit of an anomaly. One of my retro computers, a Tandy 1000 SX, is still in transit, but, in the meantime, I've been doing research on keyboard options, as Tandy decided to use start bits in their keyboard protocol rather than stop bits, and, thus far, I've been unable to find anyone who has built a converter between the two. The Northgate Omnikey is one option, and there's another non-Tandy option, but the name escapes my. I've also read comments about the Tandy 1000 keyboard being a hold over from the Tandy 2000, but I know the Tandy 2000 keyboard uses the same 5-pin DIN as IBM keyboards, but the Tandy 1000 keyboard uses an 8-pin DIN. It was unclear whether it was literally the same keyboard with a different cable, or it was just physically the same but with a different protocol. I finally tracked down the technical reference to both the Tandy 2000 and the Tandy 1000 and reviewed the keyboard sections, and discovered that they are, indeed, identical aside from the connector.

According to the technical reference manuals, both keyboards share the same scancodes and the same timings, and everything in the Tandy 1000 manual is also in the Tandy 2000 manual. The only difference I could find in that section of the manuals is that the Tandy 2000 manual includes the keyboard's schematic, while the 1000 manual does not.

Finally, another Tandy anomaly is the naming of these two computers. The Tandy 2000 is the older of the two, and the 1000 is an entire line of computers that came after. I expect that Tandy updated the keyboard to the 8-pin DIN solely to cut confusion, as an IBM keyboards of the era had the same connector but was completely incompatible.

Sunday, May 21, 2017

Retro computers

The first IBM compatible PC that the family had back in the day was a Tandy 1000 SX, which we had upgraded to 640K and, eventually, a 2400 bps modem and 40 meg hardcard. Eventually, I inherited this machine and when it became long in the tooth, I replaced it and gave it away. Now that I'm old enough to really feel nostalgia, this is the one machine I regret getting rid of above all others.

My wife, being the wonderful person she is, picked up a Tandy 1000 SX off of eBay for a really good price, and it is on its way here. From the pictures, it has dual 360k floppies, a modem of some sort, a dual serial port card, and appears to have been upgraded to 640k. What it doesn't include is a CGA monitor or a keyboard. The monitor I can use an adapter for, but the keyboard isn't compatible with many other keyboards in existence. There is a new-old-stock Tandy 2000 keyboard up for auction, but while the keyboard appears physically the same, it uses the more common 5-pin DIN instead of the 8-pin DIN of the Tandy 1000. I don't know if they are the same aside from the cable or not. There is also a used Tandy 1000 SX keyboard available for a bit more. The 2000 keyboard is expensive enough that I'm not sure it's worth risking incompatibility once the correct cable is built. So, I'm likely picking up a keyboard for more than the computer cost. ;) There are some upgrades I plan for this to make it more usable, but I'll detail those in future posts.

A fairly recent addition to my collection is a 64k Tandy Color Computer 2. I have no storage device for this, but plan on using a Raspberry Pi to overcome this.

I also have a complete Apple IIe system and a Commodore 64 system in my collection. I plan to eventually add a Tandy CoCo 3, a TSr-80 model 4p, and and early IBM.... I'm keepimg my eye out for a deal on a 5150, 5160, or 5170. I'd also like to have a 486-class machine and an original Pentium-class machine. I'm happy enough with emulation for these two that they're nowhere near as high on my wish list, though.

Stay tuned for additions and upgrades, and a full report on the 1000SX once it gets here :)

Monday, May 1, 2017

Westin Hotel

The hotel finally agreed to refund one of the two nights of my stay since I had to cancel my Penguicon trip. Still waiting to hear from the con themselves about whether they will refund my registration or not, but this is at least partial success :)