Mystery Mod On A Radio Shack TRS-80 Color Computer

[@MickeyMousePark]

i was manager of a Tandy Repair Center in Santa Rosa CA 1982-1986.. Trivia: the warranty seal if it is white letters with black background it is from manufacturer ..if it is black text on white background it is from a service center..there may be a hand written 4 digit number on the sticker starting with a 7 which is the service center number... if you look at the ad at: 1:41 those have square plastic label (near heat vents) showing the amount of RAM.. a very common mod at the time was to remove plastic label under it is a round hole which a LED fits in perfectly to add a power indicator ..not authorized by Tandy.. 12:27 There was a mod by Tandy to put pull up resistors on some chips.. it was hard to see since your arm was in the way on close up and imposible to make out when the camera was not zoomed in ..at 14:16 the resistor connected to c60 is not a Tandy mod.. When people brought computers into a service center with consumer mods our rules were we removed all consumer mods put the parts in a zip lock bag fix the computer put a warranty seal on and return the computer and zip lock bag to the customer..

[@brentboswell1294]

The keyboard is the late CoCo2 keyboard. RadioShack stores sold that keyboard as a hobbyist part. I remember seeing it hanging from the pegboards in my local RadioShack store back in the day. As I recall, the cable was different between the CoCo and CoCo2, requiring a bodge connector to allow the ribbon cable from the CoCo2 keyboard to the CoCo motherboard.

[@themax4677]

I have my father's CoCo 1 and he had some interesting mods of his own. He had replaced the chiclet keyboard with the same one this CoCo of yours has. He also put in a power LED as well as piggybacked ROMs that could be swapped via a switch. Unfortunately the ROM hack has to be removed due to failed legs and I replaced his red LED hooked up with old lamp cord with a green one with smaller wiring. I also added HDMI support via the board made by Alan at AC's 8 bit zone. Produces fantastic picture and and do color palette swaps. Well worth checking out. Forgot to mention that it's RAM was also upgrade using Apple branded chips!

[@RetroHackShackAfterHours]

Cool!

[@KlodFather]

@@RetroHackShackAfterHours - Radio Shack Computer Center. The bigger business computer stores and large mall locations selling model 2 12 16 and the bigger tandy lines.

[@wmrg1057]

Radio Shack sold a CoCo with out a RF modulator for schools. It was to "deter" theft as it would not "work" unless you had a composit monitor, which was rare outside side of broadcast facilities in the 80s. We had a pair of them at a radio station. Wrote a custom program for call screening for a talk station. The screen size was just right for the number of phone lines and an info line to the host. To get their attention, we could flash the screen. Worked well for the three years the station was around. Still have the systems around in storage

[@RetroHackShackAfterHours]

That's cool!

[@robertcase2961]

I worked for Radio Shack in '89/'90, toward the end of the CoCo's lifecycle. We were selling them for $199.95 at that point. I remember looking at the display we had for the CoCo 3 and thinking "I should pick one up just for the heck of it". I never did, now I'm kicking myself for it. 😕

[@brentboswell1294]

RadioShack later released Extended Color BASIC 1.1. It required the Color BASIC 1.3 ROM. Later CoCo disk controllers required the newer ROMs. You can upgrade any CoCo with those ROMs. If you ever encounter a CoCo with Color BASIC, you upgrade it to Extended Color BASIC by plugging the Extended Color BASIC ROM into the empty ROM socket 😊

[@kc7klz]

How about BYTE Magazine. I used to read that all the time in the 1980's.

[@johnglielmi6428]

The CoCo was my first computer as well, I still own my CoCo 3 as well. Had a Tandy Sensation but I no longer have the PC. I also have a Commodore VIC20, but I preferred the CoCo . Commodore sign, Atari sign, and Apple sign

[@mikenelson6630]

One of my first jobs actually was working at a local small town Radio Shack. To my knowledge, Radio Shack did NOT ever sell any user installable upgrades for the CoCo1, CoCo2, or CoCo3. While there were definitely keyboard upgrades available, they were all 3rd party upgrades. I even saw a memory upgrade to either 512K or 1MB performed live at a computer show in Chicago. It involved careful soldering of a sort of 'Y-bridge' on top of a 40-pin chip on the board, that had pins sticking from the top, which then accepted a daughter board. Needless to say, it took great skill to solder directly to all 40 pins of the (PIA?) chip, to complete the upgrade. The CoCo1 was designed to use RF output to connect to ANY standard TV set, and was limited to a screen size of 32x16 for clarity on any TV. At the show, I even saw the CoCo1 with serial number 000001 !

[@DevilsHandyman]

My first computer was the Coco 1 with 4KB of RAM no extended BASIC. I eventually upgraded it myself to 16KB for $150 back in the day but never got the Extended BASIC.

[@rivards1]

Two options for your sign: either "ComputerLand" (goes back to 1979) or if you want to go WAY back to 1975, "The Byte Shop". Both logos are online. That looks like a great idea, using the garage door panels to mount them. Maybe skip a little insulation under them for better temperature control!

[@CoreyDeWalt]

Excellent idea!

[@CoCoNationNews]

The monochrome mod works really well with a lot of the higher end word processors, spreadsheets, etc. (like Elite Word/Calc, Telewriter 64, VIP Writer/Calc, etc. Made the graphics higher density character sets like 51x24 and 64x24 much more readable, and even 85x24. As others have noted, I am fairly sure that you have 64K instead of 32K of RAM (BASIC will only see 32K). You can test by playing a 64K game (Sailor Man is a popular choice) or booting OS9 or NitrOS9 level 1, both of which require 64K. (I never personally saw the "half bad" 64K RAM chips; the only true 32K RAM machines I saw were using 16 16K RAM chips, piggybacked and connected with a wire across them, back when 64K RAM was quite expensive).

[@RetroHackShackAfterHours]

Thanks. I'll try it.

[@rofbungle8572]

I'm glad I'm not the only one who uses a whiteboard for a repairs to do list!

[@genetomblin2883]

Color computers across the board had power supply heating issues. They were linear power supply s(not switching supplies as on most later machines. The model 1 here has a TO 3 pass element transitory. Later models had a TO220 case device in this place. The power requirements continued to increase with each version. The CoCo 3 could be expanded to 512K of further adding to the all ready overloaded 5 volt supply.

[@melkiorwiseman5234]

I played around with a CoCo for a while and my "Magnum Opus" on it was a machine code routine designed to do something not supported in hardware, which was to put alphanumeric characters onto the graphics screen (you had to literally draw them using BASIC commands). My machine code allowed you to use the high-res (256x192) graphics screen to print 32x24 characters using the full IBM extended ASCII character set (the table containing the character set was far larger than the program). The code included a lot of fancy character-manipulation commands, and even a command to customise characters inside the table or print a custom character without having to redefine one of the existing characters. With my routine, you just used a USR call and gave it the string of characters to be printed (which could include control characters such as CHR$(26) to clear the screen). There was even software controlled printing modes, such as "overwrite", "or" and "and" so that the text could more easily be mixed with graphics.

[@RetroHackShackAfterHours]

Nice!

[@melkiorwiseman5234]

@@RetroHackShackAfterHours I thought so too (of course). 😄 I've barely covered a quarter of the features I included in the code. The biggest one was relocatable code, which meant it could be shoehorned into any convenient RAM location. What I'd usually do was to clear 6 pages of graphics memory, which was 4 for the hi-res screen and 2 pages for my program to reside in, so there was no need to do a custom CLEAR command before loading the BASIC program.

[@thomas-i5o7h]

Yes, I would be very interested in your Tomy Tutor video.

[@ferrellsl]

I had a Tomy Tutor for a short time in college back in the 1980's. It was a great little computer but I sold it quicky because I couldn't find peripherals for it such as a tape drive or disk drive.

[@JamesSmartt]

was my very first computer as well, started with 4k and hacked it quite a bit over the several years I used it, I believe we (Dad and I ) managed to force 128k of memory in it, seem to recall having to switch banks (or something) to be able to use it all. Also added a power LED and a video inverter, among a few other things that I can't remember. Loved that game as well!

[@daledickey8400]

This is the same model Coco I have, bought in 1982 from Fort Worth TX via mail order paid $499. The keyboard was sold in RS in 1985 as a special purchase $5 limited quantities per store, I would buy and mod for friends, 3rd party keyboards started at $49 up to $129 plus shipping. 1989 I bought a Coco 3 still have that too. 1985-1986 I worked for Radio Shack with mixed feelings how customers and employees were treated. But before I would spend hours in store as a customer always going there first in the mall meeting back up with my friends later in the record shops..

[@lamerdan]

New sub that was pushed over the edge because you used the boob analogy which made me laugh.

[@humidbeing]

A CompUSA sign would be cool. Maybe too new?

[@RetroHackShackAfterHours]

Yeah. Probably, but I like the idea.

[@CoreyDeWalt]

I had the same idea :)

[@MaggieKeizai]

The Amiga and IBM logos have some good, designy visual interest, those would be good background signs.

[@rager-69]

The color Apple logo, the Atari logo and Commodore logo would be good candidates for signs. I guess you could also do an IBM logo.

[@Daveyk021]

Maybe a period correct IBM sign?

[@CoreyDeWalt]

I like that idea

[@Ghozer]

"Tomy" as Toe-mi... not "tommy"! Also, the earliest use of the @ symbol, was in the 1500's

[@harveysmith6337]

Tandy Computer Centers had their own signage separate from the retail stores.

[@horusfalcon]

You don't work on it much that I've seen, but a DEC sign would be cool. Cool little Coco. Somebody got adventurous back in the day...

[@chuckcrizer]

It was a right of passage to mod your Coco.

[@thomas-i5o7h]

I remember the Coco. It had a lot of possibilities for expansion and improvement, but Tandy, in their infant wisdom, did next to nothing to pursue that.

[@vanhetgoor]

The Radio Shack always had exotic electronic parts on blisters, very high priced parts, but sometimes they were the only one that had them in stock. Always Radio Shack had Realistic audio equipment, it looked nice but it was plastic with metal paint on it. The paint was off and so was the warranty. I have two parts of a Tandy Radio Shack TRS-80 waiting to be joined together. The paint is off and some screws lost the holes where the needed to fit, not even the holes are gone, so did the screws. The plastic housing of the TRS-80 is the most Chinese I ever saw, it breaks at strategic places, near the hole and where things come together. What I very dislike about the TRS-80 is their software incompatibility with other TRS-80 models, some have a Z80 processor and some have the 8609 processor (the Coco). That was the biggest flaw they made. I like the Z80 TRS-80 except for the cabinets that were faling apart. Ef You, China, cheap plastic, it is a shame!

[@MickeyMousePark]

the coco processor was Motorola 6809 which at the time was a real oddity ran OS9 disk operating system.all other models ran TRSDOS.. compatible Models were 1,2,3,4,4P etc (note Model 2 was 8inch the others were 5.25 inch floppies) which all ran Zilog Z80's but not compatible with Model 12,16,6000..which used Motorola 68000 processors TRS Model 12/6000 had Motorola 68000 and Zilog Z-80 ..the Zilog Z-80 handled I/O and Motorola 68000 handled everything else... in the 1980s (pre-IBM PC) all manufacture software was only compatible with their own platforms.. Tandy first entry into "PC compatible" market was the Tandy 2000 which had a Intel 80186 processor completely compatible with Intel 8086 and Intel 8088 ran TRSOS and MSDOS upgradable to 720K ..they were not sure this MSDOS thing was going to catch on or not and covered both bases..next was the Model 1000 8088 with MSDOS and TRSDOS and Model 1200 running 8088 ..with MSDOS...and the rest is history

[@kennymurray3249]

your mod might look nice on a commodore monitor.. they separated the video signals to make it more clear.. could be a mode to do something like that...

[@dougd1115]

It sucked using the CoCo on RF. I ended up returning my CoCo 2 because of the interface it would generate on TVs you would use it with.

[@dh2032]

the silver is great condition, new out box look, abit to new, I you only had look at it funny, and the black plastic would show from under the silver paint

[@mikenelson6630]

Dungeons of Daggorath - cool game, I still have the cartridge, but It's been way too long since I've run it.

[@RetroHackShackAfterHours]

Play it!

[@rleeAZ]

That's a coco 3 keyboard... pretty sure the arrow keys won't do anything unless (maybe) you are running OS-9

[@gerrymichaud3851]

Oh yes I had one of those. Took a class in basic to learn how to play with it

[@nickolaswilcox425]

commenting just based on the thumbnail, no idea what the third plug is for but that looks like a magazine published composite mod, or at least thats what i was told the one in mine is and it looks pretty much the same, the third plug though should be interesting to find out

[@CoreyDeWalt]

Maybe CompUSA? I know you are Canadian though... maybe they were still in Canada? PCMagazine would be neat too.

[@jeforiley8236]

Perhaps you could have an original Apple sign in the background… perhaps a little obvious, but nothing is more iconic for this era!

[@megamarco777]

I've got a CoCO 64k that I can't wait to fire up. But I don't know what to do with it!!! It literally has nothing with it, but it works. Any ideas?

[@WilliamHostman]

Signs? InCider Magazine, Beagle Bros... Or at those too applecentric for you?

[@rager-69]

What is a Tomy Tutor? A computer or a learning toy?

[@JimmyCall]

You're playing the best Coco game available!

[@d.tracylane8661]

I beg to differ - Sands of Egypt rocked!

[@RayMillTN1]

I used to have that keyboard.... no idea where it went 😞

[@chuckcrizer]

They were called "calculator keys."

[@keyster747]

sign: aladdin's castle

[@idahofur]

Computer Land for a sign.

[@nopenottalib4366]

The correct pronunciation for the Tomy Tutor is NOT "tommy" ... it's "toe-mee." 😉

[@thesilentcitadel]

Agree Dungeons of Dagorath was the bomb

[@Siktah]

You need a Tandy and a Dick Smith Electronics sign

[@Mr.RyanButterly]

Newton's apple Sign.

[@ocsrc]

Any chance you know someone who can do 3D printing ? I have a keypad I need recreated It is a KDM-7 16 buttons The pad is 2 inches by 3 inches I did a video on my channel so you can see it Please let me know if you can help Thank you Bill KC2OVX

[@GrymsArchive]

Thank the gods for the *L Key* -1

[@AlexEvans1]

It could just as easily be a 64k machine.