TRS-80 Model 4 High Resolution Addon 

Tandy/Radio Shack really had a knack for finding ways to position boards so that you can't easily do diagnostics on a running system.

Whenever I see a computer playing tic-tac-toe, I think let's play thermonuclear war.

Back in the day, those RF shields were very necessary. I remember my parents making me shut down my TRS-80 model 1, because with it running, it interfered with the family TV. The conductive paint on the inside of the plastic was a terrible RF shield, and since the TRS-80 clock was run off of a standard color burst crystal oscillator (IIRC), it radiated RF in the same range as the TV was using, and it caused issues. Also, i would have some odd graphical issues if certain flourescent lights were on. Again, RF interference. These issues generally don't occur today, but back in the day, people were still figuring this stuff out.

It was common practice back in the day not to have a floppy in the drive when turning on the machine because computers of the era didn’t always have the proper protection circuits to keep power surges from going through the drive heads and wiping out a sector when you first turned on the machine.

As a former RS salesman/Asst Mgr/manager, thanks for keeping this running. Love me a Trash 80

Did the designer of this thing happen to own stock in a CRT company? Sheesh that’s a tight squeeze!

6:59 Damn, that was unnerving... Who needs a horror movie when you can watch a guy shit his pants from fear while taking apart his beloved, rare, and internally awkwardly designed retro computer?

I find it amazing they were still making these old relics in 1984.

It’s sad Tandy died out. It was such a big player in the 8-bit era, it’s sad to see their impact and legacy fade away.

Man that brings back memories. I ran a very small, local BBS off a Model 4 back in the late 80s.

I just went down a rabbithole here lol. I thought, "Oh, they made a 4? I thought they only went 1-3." Then, I looked up the computer series, and saw yes - they manufactured TRS-80 Models, 1, 2, 3, and 4. I then thought, "Hang on, weren't these called the Color Computer?" and then went on another tangent, finding that the Color Computer was a completely different piece of hardware based on a unique chipset, despite sharing the TRS-80 name. And those did only go up to 3, with the CoCo3. From there, things just got weird. You had the Model 12, the Model 16, the Model 100, the MC-10, the Pocket Computers and PT-210 - 90% of which are completely incompatible with each other. Radio Shack was weird, man.

You are living your best life. I wish i had the drive to hunt down all the equipment you do. I envy you so much!

If you want to clean the machine without damaging it, try steam. Steam is an incredibly good cleaner, especially if you pre-treat the case with some basic all purpose cleaner. By using steam you won't have to agitate or rub on the paint. Though steam can be hot, there isn't much of it and so it doesn't have a lot of heat and most likely would not damage the paint.

very impressive to see true graphics on a machine that basically is text only! very nice!

I have one. Bought it knowing that at least the power supply is dead. I've done a few restorations, including soldering in a replacement flyback in a Macintosh 512k. Seeing this video makes me think maybe I should sell the Model 4 to someone a bit more capable, as I'm just a hobbyist.

If you want a monochrome CP/M machine with high res graphics that can play games, get an Amstrad Word Processor. Amstrad created a standalone word processor in the late 80s based on CP/M that also had a ton of games ported to it. The one downside is the machines (there are multiple models) use 3 inch disks, not 5.25 or 3.5 inch disks.

I am not sure if you are someone who reads your RU-vid comments, but I hope that you do get this comment and the other I just left on this video and understand how much I appreciate the videos you make and want to thank you for that.

Nice work to not neck the CRT. I was a bit nervous just watching that.

This is great to see. A model III was my first computer at four years old.

Very cool graphics! The Mandelbrot set was the highlight.

Thank you for scaring me away from ever wanting to own a TRS-80 Model 4!

I have an original one of those in my model 4 that I bought when I was in college, also fully upgraded to 128K. I did kill the CRT in the early 2000s when I tried to clean it up an d get it booted. One of these days I'll either find a replacement CRT or an LCD panel alternative. Cool seeing one of these running.

I miss my old Model III a lot a long with a Tandy 1000HX I think was the model name.

Your videos are so awesome covering what seems like a quick or simple topic, but end up so in depth and intriguing! I love it! Have a wonderful day! 😊

I have one of these model 4s. What a great machine. I installed a gotek and replaced those known to blow capacitors. My arrow keys are different than yours too. The left/right are on the right side while up/down are on the left side of the keyboard

The looks of black and green CRTs screams early computing to its fullest. Granted, I'm from the 90's and we had our C64 hooked up to the TV back in the day, my father's 286 however came with a black and white CRT that never left such an impact on me the way that strong and bright green does.

I have one in my 4P, love it

Man, it is crazy that Tandy couldn't be bothered to make the plastic case just another 1/8" deeper. I'm sure they lost a good number of picture tubes in production due to that lack of clearance.

You inspired me..i built a board for my pc ...all it does is take the front I/O and brakes it out to 5 connections to each on the board...a spliter now i have a cool power button box on my desk but also can still use the switch on the pc itself and have more power/hdd lights ...its not much but im proud of it seeing as how i did it from scratch

That CRT neck is so God damned close to the muthaboard. Taking that thing apart would give me a tension headache. Great video and very interesting upgrade. I missed out on these old computers other than the family C64 that I still have.

Just an observation: "High" resolution is always relative to the capabilities of the machine and of course the technology of the time in the retro world. The model 4 was late in the TRS-80 timeline, but still before the PC clone wars. Perspective, 1983/1984 would have been when the C64 was taking off like a rocket (320x200, but in COLOR!) Tandy had the COCO for about three years already, but nobody considered that "High" in any dimension and especially not graphics (or the keyboard!) The Trilogy computers were upgraded again and again and had nifty third-party solution for higher graphics modes. So you really had to spend some coin to get decent graphics, like the IBM PC with a CAD card. Or get something dedicated for a workstation like the Sun or DEC machines. I had a DEC workstation around this time with what we would call "2K" resolution today and it was hella expensive.

All hail the TRaSh-80. Any computer is automatically more awesome with a video card upgrade!

Great video! A suggestion, you should not activate the ads on your videos when posting only to your Patreon supporters. This would be an additional benefit for supporting you! Thanks.

Does anyone else remember 1984 ? I was in kindergarten, but even being a little kid I remembered it being a better time . Life was much simpler back then . Great video , always enjoy each one . Especially because it brings back memories of my childhood with all the vintage stuff .

My high school had a lab of these and some variants. We all learned computer basic and pascal, and perhaps cobol on them, but those last two are vague memories. I vaguely remember hitting that red reset button by accident, or another student would walk by and poke it...We ended up calling it the panic button. If you held the button down, after hitting it, and didn't lift your finger, you still had a chance to save your work, but lifting the finger was certain doom... I always liked those old machines. Fond memories. I think Turtle was also a program we used, if that is possible (it could have been on an Apple as we had one in the corner...) The person who was last to class had to work on a strange plotter/printer with a keyboard, as we were short one computer. You usually ended up watching others work... Eventually, much later my school upgraded to IBM clones. Not sure what happened to these old machines.

Next episode: Shelby opens up his TRS-80 *yet again* when he finds out the floppy controller can't do double sided drives and there's a reproduction controller that can do it.

Remember that Radio Shack had thousands of these to service. I believe you can disassemble the Model3 or Model4 on its side. When splitting the case just keep it on its side and you avoid necking the CRT

I really love your videos, and I love the hobby. I have a large group on Facebook that I am trying to expand onto RU-vid and you for sure give me inspiration to do so. It's really hard for me to be on camera though and that is what I struggle with the most. I have loads and loads of retro towers and hardware I got from a family friends and I could sure use a friend like you to help me with knowing a bit more of what all I have and what I can do with it. I am a computer enthusiast, and I am very knowledgeable about computers and computer hardware but this older stuff I am not as knowledgeable about even though I am very interested in it.

The hi-res looks great! Nice job and thanks for another interesting video!

I very much appreciate you speak in metric more and more 🙂

The first computer of my household, my father got it back in 87...

Ah, the Trash 80! I both loathe and miss you!

I like how comment sections like this have become nostalgia hubs for the retro 80's life. I feel it too. Really good demo, man.

Great video as always, I really like how well you put these together. There's no way I could run a camera that good on my own either haha. Are you doing some kind of noise reduction to your audio? I kept hearing it chopping off parts of your speech and sounding almost robotic at times. The desync between the audio and your mouth at the beginning of the video was also driving me crazy haha

Put 'X' on the second layer from the left at column one row two. For the win. I had to comment. I like the Fractal Forge software it's odd and fascinating seeing the different colour patterns.

Nice! Now time to reinstall that floppy back into the IBM machine. I remember a skit that Red Skelton did many years ago I believe in the character of Willy Lumplump the intoxicated businessman ( I could be wrong as to the character ) he dispensed a drink from the machine behind him and turned to the audience and explained what IBM stood for, "INSTANT BOOZE MACHINE".

I so wish I had the space for some retro hardware, but I will have to make do with my TRS-80 emulation which supports high-res mode. Thanks so much for this. It does my heart good seeing as my first computer was a Model 1. I kept it for years before selling it to a writer to do word processing.

Woah! Now you can check all your Sbemails with the crispest, freshest graphics known to man.

Omg I had one of these many years ago lol. I think I had a tape drive with it lol.

I had one of these machines growing up.

Ian Maverick?! Oh damn I know that guy. Bought a chassis and CRT off him.

Awesome, dude!

That tic tac toe game is pretty cool.

I'd just grind some of the RF shield out where the neck attaches, make it real thin in that area.

I used to be comfortable opening the Model III and 4. That was a long time ago. Did you notice on your M4 the scuffs on the monitor side of the motherboard aluminum (near the top above the insulating pad)? You can see at 7:50 the neck of the tube has rubbed on that aluminum.

Awesome Video

Like WOW MAN. Just takes a bit of high res gaming to turn TT into Otto the bus driver :)

It's amazing how a terrible nickname killed the TRS-80 and may have echoed the demise of Radio Shack. The Trash-80 was the nickname and it was as common as floppy drives in the 1980s.

🎉I rebuilt my model 1 into a model 4 case purchased as a spare part, it came with the drive mounts so I was lucky. I mounted the board across the back and have the same issue, if the case is not sliding across the board its too far foreward and I'm risking my tube. Mine has two Mitubishi 80 track double sided drives in the top drive bay, I'd love to fit a cassette tape drive in the bottom bay but I've never found a suitable mech. There used to be these early front loading HiFi tape recorders where the mech sloped bachwards behind the front panel so it was kind of flat, I thought one of those mechs with some lighting would look nice..... I did have a high res board, but of my own design, I pulled it when I did the M4 rebuild, maybe I should revisit it, maybe make a compatible to the M4 version? - pipe dream.... The paint on mine has stood up really well, all it needs is an owner who cares, rather than one stripping it and selling it as a 'for parts' special.

A possible solution to the cleaning problem ... obtain some dimethyl sulphoxide (DMSO for short). DMSO is possibly THE most effective solvent on the whole of chemistry. Which means you won't have to rub the paint hard to shift even fairly stubborn stains. But you WILL have to take precautions while using DMSO, because it can be absorbed through the skin AND carry with it a host of other substances into the bargain. It's used for transdermal medication for that reason. So, you need to find gloves that DMSO won't penetrate. Next, you need to conduct your cleaning operation in a well ventilated area. Ideally, wear a face mask while using this substance, and if you're able to perform your cleaning outdoors, so much the better. DMSO dissolves substances that other solvents can't touch. But there's a price to be paid for this - it might dissolve your paint as well! So you need to test for this before committing yourself to this sledgehammer of a solution. Also, DMSO can be expensive to buy. The advantage being that if you are able to use it, it will operate at room temperature - no scalding steam to worry about. But you need to take precautions as you would with ANY unfamiliar chemical. Not especially toxic itself (it wouldn't be used for transdermal medication if it was!) but if anything toxic dissolves in it, DMSO vectors that dissolved toxin through your skin VERY effectively. Professional equipment cleaners use DMSO for the really challenging jobs, but of course do so in a laboratory level environment. It's worth a try if nothing else works, but you'll need to undergo a LOT of preparatory work before uncorking the bottle.

Love these old TRS and great video! Question to the community: I have a TRS80 3 with two drives, however there is no a termination pack resistors installed in them. Where can I found one that works with these floppy drives?

amazing

The bus termination pack only needs to be in the drive at the end of the cable, hence the name.

Seems like a Hercules upgrade

If I were the one who designed the Model III/4, I would have looked to the Commodore PET for how to do the case.

Double-density 5.25-inch drives of any kind are getting stupidly expensive...

All you have to do is throw the black cloth over it. Say the three magic words. And knock on wood. Magic happens

have you tried a clay bar like they use to pull trash out of car paint without damaging it?

I am so jealous

With that mod, could you in theory even run something like AutoCAD if available for the Model 4?

Lol tech tangents and the 8 bit guy are the only reason I have any interest in vintage computers

I had one of these 35years ago, I think I paid £20 for it from the Birmingham rag market, ended up throwing it away when power supply died a year later, I'm sure I could have fixed it now but I was about 12 years old when I threw it out, and I didn't know anything about smps repairs.

Are there any modern games for this setup? Sounds like PetSCII Robots could be ported to it.

Awwwsome

If thats bit pipping in 80colum mode,its about 580x496

How about a office your 2024?

I would just put some black duct tape over the ibm logo. or if you are creative, design some period correct sticker

Hi, would be cool if you made a video about mTCP, i'm trying to set it up and i'm having no luck

Whomever designed that case is a masochist!

If the crt's for these computers become just impossible to find, which I'm sure will eventually happen, I wonder if adapting an lcd screen would be a viable solution to that problem.

I’m just wondering why you didn’t upgrade the amount of ram on the motherboard, while you had the machine open ? it looks like some of the ram sockets empty.

Why don't you replace the tube with the shorter model one?

To each their own, but having a wrong branded floppy drive wouldn't bother me.

Is there a “case badge” to signify the Hi-Res Board is installed?

is the audio a tad out of sync or am i going crazy?

You forgot to test the "new" drive...

Such a shame you didn't have the RAM chips to fully populate the RAM while you had the machine open!

I wasted my childhood writing fractal programs for computers without graphics. Thanks for the PTSD.😉

this would of been like having a shitty sanyo monitor then witnessing an 8k monitor

Wasn't the IBM pc floppy drive dual sided (360k) and all the TRS 80's single sided???

⚠️ Video starts with audio out of sync

I cringe every time I see you switch it on with the disk in the drive. That was always verboten. Turn it on, insert the disk, hit the reset button. Turn off was remove the disk before removing power.

Not quite the best it can be. You need to upgrade it to 128k.

There's a reason to why we Europeans say "Trash80"... :-)

They are not difficult to disassemble... You just have to pay attention, and be careful...

16:53 is anyone else seeing what im seeing?

try installing a hdd 640k

I absolutely *love* this guy for being interested in the same nostalgic shit into, but I can't possibly be the only one here who is concerned by his lack of skincare. Boys, I don't know if you realize this, but It is possible to be a geek while still caring about your appearance! Dude desperately needs to set some of his RU-vid money aside to pay for a dermatologist. Those acne scars are *extremely* distracting; so much so that they're a major reason why I don't watch this channel as much as I should, despite the fact that every video he puts out is pure gold. You gotta take care of yourself if you want to be happy, healthy, successful, and wise!

If those power supply rifas weren't already replaced,you will have to remove the cover and replace them...

over-active hands