TRS-80 Model III with an internal LCD video display...

[Omega-TI]

Does anyone know of anyone who has modified the TRS-80 Model III or IV with an internal LCD display as a replacement of the old CRT?

 

[Keatah]

Thank god I've not seen one yet. A classic shouldn't be touched, bastardized, mutilated, or anything like that.

[TPA5]

Thank god I've not seen one yet. A classic shouldn't be touched, bastardized, mutilated, or anything like that.

 

What if the CRT in the machine is beyond repair, do you let the machine rot away while trying in vain to try and replace the CRT, or do you install new tech that allows the classic machine to live again?

 

 

 

Back on topic, I've personally never seen it done. How would you convert the signal to digital to work with a modern LCD screen? Would it even display correctly? I certainly wouldn't want to try it on a working machine, but if it was a machine with a dead CRT it could be worth tinkering with.

[Omega-TI]

Yeah, some classic car guys like original, some like the resto-mod approach. I guess it's different strokes for different folks. If you look at the photo of the TRS-80 above , it does not have the original drives, it has half-height drives and Lotharek unit installed. Not exactly a stock unit.

[+sm3]

While not related to the Model III or IV, I recently discovered this device for the Model I, in case you have one of those: http://home.comcast.net/~bartlett.p/MISE/

 

It lets you use a VGA monitor on your Model I, among other benefits of course.

 

Ian Marvic from Australia fixes and sells all types of TRS-80's: http://ianmav.customer.netspace.net.au/trs80/

 

He may be able to help you locate a part or provide one for you. He was a source for a recapped power supply that fixed my Model 4P. I also picked up one of his hard drive emulators (FreHD).

 

Shipping of course isn't cheap, but at least the option is there.

[+save2600]

Gotta be easier to repair a 12" b/w CRT than trying to squeeze a flat screen in there and messing with video converters and up-scalers.

[Tempest]

Such a bastardization should never be allowed. You're a bad man for even contemplating this.

[John_L]

I was reading a blog recently about a guy putting a flat screen "in" a model III, but he had it all hacked such that the LCD was shquished onto the front, and it looked horrible. To do it right, you'd probably want to use a 10-12 inch flat screen, the trick would be to figure out the Mod III's video circuitry. The model III was basically a redesigned model I, and the Model one did use a chassis/case from an RCA TV. Tandy put in their own electronics, and I know nothing about the video output of a Model I or III as it was all proprietary stuff.

[Tempest]

The TRS-80 was a giant kludge to begin with, so adding something like this might be nearly impossible.

[John_L]

The TRS-80 was a giant kludge to begin with, so adding something like this might be nearly impossible.

I wouldn't call it a "giant kludge". It was esentially a redesigned version of the Model I that eliminated some of the complaints. The model I was notorious for the amount of RF it threw off. You could probably charge your cell phone sitting next to it (if it didn't kill you from radiation poisoning!!!). Just kidding, but that, along with connector issues between the CPU/Keyboard and the expansion interface and external drives meant you had to have a power strip to plug in the CPU, expansion interface, monitor, and each disk drive. 5 power plugs plus connector cables running all over connecting the equipment made for a huge footprint on the desktop as well as the spagetti of cables to put it all together. The Model III however fixed all those issues by integrating all the components into a single case/single power supply configuration, it had a sexy design for it's day, and it was alot lighter than all the components it replaced, and was 99 and 44/100 percent compatible with model I software, had a huge software base the day it came out, had a ton of business applications, games and utilities made for it. Also the case design for the follow up computer, which could expand to 128k was almost identical with the exception of the RS232 pointing out the back (instead of the bottom like the model III), and the computer itself was also packaged into the "luggable" model 4p.

[Omega-TI]

The 4P if I remember correctly, did not have a cassette port like my MOD III, so one could not get audio out for games like ROBOT ATTACK. Now the MOD IV was really cool because it would run MOD I & III software, but would go 80 columns in IV mode, which was really nice when using the word processor. It really rocked with a green screen!

[+sm3]

The Model 4 (with green screen) is my favorite TRS-80 computer, but they are kind of hard to come by these days, at least for me since I buy only via eBay. Having a spare is one of the reasons I picked up a 4P. There always seems to be a 4P on eBay.

[Bill Loguidice]

I prefer the ones with black and white monitors over green screens. I've always loved the all-in-one form factors, and a Model III (in school) was my first exposure to such a design. This is what I own as it relates to the TRS-80, though not all of them are working 100% (a common issue with these systems):

Tandy TRS-80 Model 4

Tandy TRS-80 Model 4

Tandy TRS-80 Model 4P

Tandy TRS-80 Model 4P

Tandy TRS-80 Model I

Tandy TRS-80 Model I

Tandy TRS-80 Model III (parts only, missing monitor and motherboard components)

I have a FreHD, but my two Model 4's messed up some of the boot floppy disks it came with.

[+sm3]

Bill, quite the collection! Did you see that chip from Ian Marvic that eliminates the need for the boot floppy? I don't have one myself, but considered getting one. Also, you could use an HxC to either create a new floppy disk or just use it to boot. I use the HxC on my Model 1 to boot most of the time, my real floppy drive is just sitting there to look good

 

I suppose if you are handy you could just make your own eeprom. Ian would provide the image for you.

[John_L]

Radio Shack was in development of a "Model 5" that never made it beyond prototypes, but TRS-DOS for the Model 4 had provisions for sound and color that were probably intended to be sold as addons that never came to being. I think that's why the 4p didn't bother with the cassette port, as any sound they would have done would have included the cassette hardware on the sound board for backwards compatibility. Also, remember, back in those days, sound was thought of as something that would only be useful for games believe it or not. There was no digital audio or video to speak of back then, although we digitized audio with the color computer! It wasn't until soundblaster made it easier to make sound because the hardware was actually built for that purpose that everyone else realized sound was more than just for games.

[Omega-TI]

There was no digital audio or video to speak of back then, although we digitized audio with the color computer! It wasn't until soundblaster made it easier to make sound because the hardware was actually built for that purpose that everyone else realized sound was more than just for games.

 

I seem to remember the "Orchestra 90" for the MOD III...

[Bill Loguidice]

 

I seem to remember the "Orchestra 90" for the MOD III...

 

I have that. There were other sound/speech solutions as well. The CoCo series got similar stuff.

[John_L]

Although the audio quality was horrible, I loved the sound effects produced for games like Time Bandits and Robot Attack. Sound and graphics both suffered in the model I/III/4s, and what's interesting is how people found ways around the limitations. For example, the horrible 128x48 elongated block graphics were bad, yet people found unique ways to set apart their game from the rest, and some really cool stuff came out of that limited setup. I remember the Model III & up did have a high resolution upgrade that kicked it up to 640x200 black and white, which is poor by today's standards, but a huge leap from huge brick pixels to actual dots. Despite this, the add-on wasn't marketed very aggressively, and wasn't as popular as the computers themselves. Therefore, aside from some additional BASIC drawing functions added to Basic, there wasn't so much as a single game that I ever saw that used it, although I may be wrong.

[+sm3]

I keep looking for one of the high resolution boards for any model TRS-80 but they are super rare I suppose. That MISE device does emulate them, so if you happen to use the VGA output you can take advantage of it on your Model 1.

 

"Emulation of the vintage high-resolution PCG-80 and 80-Grafix devices."

[John_L]

 

I seem to remember the "Orchestra 90" for the MOD III...

Yeah, Orchestra 90 was a decent synthesizer, and there was a cheesy speech add on that sounds like Prof. Hawking, but there was no actual proper DAC for digital audio sampling and playback. Digital audio was cheated through the cassette port, but it was really scratchy. None of the sound related or graphical upgrades that were offered by either Tandy or a 3rd party ever really caught on in the I/III/IV world. Peeps seemed happy with Brixels and itchy and scratchy sound. All of those devices mentioned had limited software support. Things maybe be different these days with retro gaining popularity, but none of those devices gained any sort of ubiquity. So even today it's not too likely to see much software for that stuff because they're fairly rare items.

[Omega-TI]

I still like the idea of a flat screen, but honestly I know I could never bring myself to hack on one of these classic machines. If I had a Model III, I'd want to keep the baby stock. The most I would ever do is install a Lotharek and a green screen. Sadly though, it doesn't look like I'll ever be able to give one a safe home. I would only want one in pristine condition, but finding one would be almost impossible after all these years, and even if I did... current prices... (sigh).

[MrRetroman]

I came across this on TRS80.org

 

 

The Color-Graf

written by Matthew Reed

Color-Graf advertisement from the
January 1983 issue of 80 Micro

 

The Color-Graf was a color graphics interface for the TRS‑80 Model I and Model III. Sold by Solectronics, the Color-Graf originally cost $260 for the Model I version. That price was later reduced to $195 for the Model I version and $235 for the new Model III version. Solectronics advertised the Color-Graf from 1982 to 1983.

The Color-Graf was a fairly small unit that came with its own power supply and connection to a black and white or color television set. Installing the Color-Graf required no modifications to the TRS‑80. It just plugged into the TRS‑80 expansion bus.

Like most of the other TRS‑80 color graphics interfaces, the Color-Graf was based on the Texas Instruments TMS9918A graphics controller. The TMS9918A provided a resolution of 256 by 192 with sixteen colors (including transparent) on a color television. The Color-Graf came with a full 16K, so it supported up to four video modes and up to 32 prioritized sprites.

 

One of the best selling points for the Color-Graf was its complete documentation. Included with the Color-Graf were sample programs (available on tape and disk) that demonstrated how to work with the color graphics features. The programs were based around a set of routines that manipulated all of the features of the TMS9918A controller. Detailed documentation for those routines was included in the manual, as well as program listings.

[jhd]

I did not know that there was a colour graphics expansion available. I wonder how many of those sold. That is an expensive add-on, especially given the extremely limited software available for it.

 

There were at least two different high-resolution boards (one sold by Radio Shack itself) that used, IIRC, the built-in monitor.

 

The Model III was the very first computer that I ever used, in elementary school, ca. 1982. I do not recall that the school had any software for it, other than some games and simple educational software written in BASIC; certainly nothing commercial.

 

Once, one of my classmates had somehow acquired a copy of the submarine game Sea Dragon, and we were all amazed at the graphics that the system was capable of.

 

A small part of me would like to have one for the sake of nostalgia, but it is a large and heavy beast. I have nowhere to store it, no ability to fix it, and my once limited knowledge of TRSDOS has long since faded away to non-existent.

[Omega-TI]

I

A small part of me would like to have one for the sake of nostalgia, but it is a large and heavy beast. I have nowhere to store it, no ability to fix it, and my once limited knowledge of TRSDOS has long since faded away to non-existent.

 

I know how you feel. It's been decades since I've used TRSDOS in any real sense. Oh I've used it in emulation to play a couple of games, but that is about it.

It would be kind of neat to get a TRS-80 Model III in pristine shape, one worthy enough for upgrades, but I don't see that happening.

 

I've been investigating new avenues of upgrades for one and keeping it in the back of my mind though, you never know what might pop up.

 

[Omega-TI]

I came across this on TRS80.org

 

... The programs were based around a set of routines that manipulated all of the features of the TMS9918A controller. Detailed documentation for those routines was included in the manual, as well as program listings.

 

If the thing was based on the TMS9918, I wonder if a small board could be created that allows use of the modern F18A? That would give TRS-80 users color VGA capability on an external monitor. There might not be much currently that could use it, but it could give the TRS-80 user hope for a future with some new stuff and room for growth.