Researching the TRS-80 Coco 1/2/3 repairs & upgrades and differences between them.

So, naturally, since a TRS-80 Coco 2 is headed my way that is going to need work right away I started researching the Coco's much more in depth. I should have done a bit more before I bought, live and learn, but it's a good price for the current market so I don't regret my purchase at all, I am getting what I knew I was getting, a Coco 1 in a smaller case with a real keyboard instead of chick-let style. That's why I got it.

But I do prefer the larger Coco 1 case, just like I prefer the larger 1200XL over the 800XL, and both the Coco's and Atari's have similar footprints between the Coco 1 and 2/3 and 1200XL and 800XL. I also prefer the metallic color of the Coco . And the earlier peripherals for it are identical, internally, as the Coco 2 beige line, except for the disk drives which require the Coco 1's 12V, which was dropped with the Coco 2 for only the 5V, just like the transition Atari made from the 400/800 to the XL line. So the Coco 2 disk drives are different internally as they run on 5V only.

But after some research I've found out that the keyboards between all three are interchangeable, same size footprint and ribbon cables. So I could have gotten the older Coco 1, which on average sell for about 25-50% less than the Coco 2 as well as peripherals matching the Coco 1 and upgraded the keyboard to the Coco 2 (the Coco 3 and it's keyboard are about 3 times as expensive and the only advantage is cursor keys to the right side instead of incorporated into the main keyboard like previous versions (left & right to the left side and up & down to the right side) and and an F1 and F2 key added that don't work with Coco 1&2 OS's.

Also ram and OS can also be upgraded to match the Coco 2; 4/16K-64K. There is also a 16K version of the Coco 2 that can be upgraded too the same way. It was there low end model just like the 600XL, but had the same size case and the upgrade is internal, with sockets waiting to be filled and jumpers to be connected, just like the 1200XL upgrade to be 800XL compatible as far as memory and OS goes.

So I will be looking for a Coco 1 and buying peripherals to match it, because when I do get a Coco 1, I'll be using the Coco 2 as a parts machine for keyboard, OS and ram upgrades and replacement parts for the Coco 1.



The Coco 1 had two main revisions cosmetically. The original 4K version released to compete with the VIC-20 (3rd picture) with a black plate surrounding the black keyboard face, The later 16K stock with a grey mettalic plate surrounding the black-faced keyboard Both are up-gradable to 64K that came with a badge designating it like the badge on the 4K model shown (1st picture), 16K badges available too, with upgrade kits or dealer upgrade from 4-16K, but the 16K stock Coco didn't have a badge.

The Coco 2 had three main cosmetic revisions, just before the Coco 2 I got, a beige, 64K Coco 2 still with the larger case of the Coco 1 (2nd picture). The 4th picture is the one I'm getting, a new smaller case Coco 2, but with the same keyboard as the Coco 2 with the larger case, known by fans as the "melted keyboard." The 5th picture is the final Coco 2 revision with a keyboard with full-travel keys.

The 6th picture is the Coco 3's* only version.










*Interesting trivia facts about the Coco 3 and how it compared with the last of the low-end 8-bit market: 128K stock like the C128 and 130XE, but up-gradable to 512K like the C128 too, Atari dropped the ball on the 130XE there, unofficially though, third-party upgrades in the day covered it. On the other hand, the Coco 3 had superior graphics and CPU upgrades too, unlike the C128 (Z80 and CP/M OS is an extra, not and upgrade) and 130XE. It is actually closer to the mid-range Apple IIGS, yet still competing in the low-end market. so Atari and Commodore (with the C128) dropped the ball there. But then TANDY didn't have a proprietary 16-bit machine to compete with Atari and Commodore 16-bitters and instead went PC compatible for the 16-bit market and continued to upgrade the 8-bit line as well with better graphics and CPU like the Apple did the IIGS. Atari just kept selling the 130XE with no graphic or memory upgrade path for the 8-bit beyond it. The Coco 3 was on the market until '91.

That's why I wanted a Coco 3, plus it is still compatible with software and peripherals from the Coco 1 & 2. But I'm not going to pay $500 for one!

Of course these days even our 8-bit Atari's can be upgraded to match the last of these other companies 8-bits, with VBXE and Rapidus and the 512K, 1MB and 4MB memory upgrades we have now, finally.

 

Very interesting research there, Matt.

I know diddly squit about these Coco machines so we learn something new every day - especially on here!

Good luck with all the upgrades and purchases ahead to make this a real rock n roll retro machine which fulfils all your ambitions for it.

 

Yes, nice write up Matt. Always remember a range of game ads for the Coco in early UK computer magazines. Think the main character was called Cuthbert.

 

I'm not going to buy it, I want to restore and upgrade a Coco model 1 myself, but I wanted to show a picture of a Coco model 1 for sale, upgraded to Coco 2 specs, but with the later Coco 2 revision keyboard, not the "melted" keyboard like mine will have. But I think the "melted" keyboard on the Coco 2 I am getting will look more vintage and go with the older metallic case better anyway, just like the first model 2 with the model 1 style case above that is beige.

 

I just discovered that there was a third design change version of the model 1, that did come stock with 64K, but was in a beige case with the "melted" keyboard just like the first version of the model 2. It just has the older OS and Basic roms.

 

I figured I'd show my new arrival in this thread since I already announced it with a picture in "What's new pussycat too."


First impressions of my Coco 2 "melted" keyboard model is that the case it better than I thought, what I thought was slight yellowing and it would need a retro-brite, looks to me to just be a bit of dirt I can clean off with some glass cleaner and a cloth. It's in fantastic shape otherwise, though it is missing two of it's four rubber feet on the bottom. The same square kind that are on Indus GT and CA-2001 drives.

The "melted" keyboard is certainly a step in the right direction from the chicklet keyboard of the Coco 1, but it's feel does remind me of my 130XE's keyboard; a bit "mushy." But the keys themselves seem sturdy and not flimsy like XE keyboards. I think I may decide not to use this Coco 2 as parts for a Coco 1 and just have both, and get parts to upgrade a Coco 1 separately.

I'll open her up later to make sure there aren't already mods or upgrades that the seller may have been unaware of...

Below are a couple of pics for size comparison to it's Atari contemporaries and a close-up.

 

So I started taking screws out to open it up, and there was one screw still holding the case together that I couldn't find, until I realized it was still hidden under the warranty sticker! This machine has never been opened! Upon opening it I see an inside case and motherboard that look factory-new, not one speck of dust or dirt anywere! And it's got an empty socket just waiting for the Extended Basic upgrade, or that's for the OS9 OS, not sure yet. I have to look up the 8 ram chip numbers to make sure, but I think this is the 16K version, I think the 64K version came with Extended Basic installed. But I do have to check and the chips don't give an indication with the last two numbers being 16 or 64. I can't locate a 16K/64K jumper on the mobo though, which in some videos they have shown for upgrading ram, so this may be a 64K version stock.

 

I have a feeling this "powers up only" computer only needed it's socketed chips reseated and I felt several push in when I checked them all. I may have a perfectly new, perfectly working Coco 2 here that needs a simple case cleaning! I'll power it up later, but right now I have to go with my brother to get him a car.

By the way, as you can see, the Coco 2 had a very small board and half the case is empty below the keyboard. I do believe this mobo is even smaller than the 600XL's, I'll compare later...

 

Cheers for the updates, Matt.

So this Coco sits somewhere in size between the 800XL and 1200XL but a fair amount of under the keyboard space is pure fresh air, yeah? Will be interesting to see then how the mobo compares in size with the 600XL, as you say.

Looks in lovely condition so you may well have bagged a near pristine bargain here.

So, just to check on details once more, these beasts have the 6809 CPU within, is that correct, just like the UK Dragon 32/64?

Which, if I remember right, is also mainly casing when you open up...



Keep us posted, Matt, as I'm sure many on here will be gaining a lot of new info on these mythical beasts.

 

Yes, the Dragon is a clone that is about 95% compatible, and actually I remember in my research somewhere that with a slight mod of the OS or slight hacks of the software, one or the other, both can run each other's programs.

There was a version of the Dragon by a company called Tano here in the states for a while. Of course the TRS-80 Coco was sold in the UK and all or part of Europe, I know France for sure. That color Genie you showed earlier is actually a clone of one of the original TRS-80 machines (not Coco and used the Z80 processor instead of the 6809)model I and III's. They ran CP/M.

Below is a picture of the 600XL mobo,minus it's PBI port, next to the Coco 2 second model release. I can't wait until I get a Coco 1 and compare it to the 1200XL, I think their sizes will be very close, maybe with the Coco 1 being slightly deeper by an inch. Of course I could look up the dimensions of each, but that's no fun.

I haven't been able to test my Coco yet, as these things don't have power LED's to even let you know they are on (many people mod them for and LED and I will too) and it is only RF out, like the Atari 400 and the U.S. 600XL. This is the Coco 2 model from about '82-3 just when the 1200XL and 800XL were aroun. I can't believe they don't at least have a monitor port, but it was RF out only,even for the 64K versions, until the Coco 3 when they finally gave composite out and RGB out. So there is an easy video/S-video mod I will do, just like I'm doing for the 7800.

I had an in-line RCA to coaxil RF adapter but I can't find it! I may just end up temporarily "hot-wiring" it between it and the TV to test it...

 

Well, since I can't get connected via RF atm, I decided to start research on my specific model number. Mine is the very first U.S. and European Coco 2 model, the version I saw that was beige, but also in the larger Coco 1 style case were sold in Australia and Korea only. Apparently. It is 16K only and does need the second 8K OS chip for full Extended Basic OS, which is required if you want to use a disk drive with the system and be fully compatible with all old and new software.
So I need to buy the OS chip and install it, and they did say that even though the this model uses unusual 16K chips instead of the usual 4116's, the 64K upgrade still uses standard 4164's.

Luckily I have a ton of 4164's on hand pulled from my on hand from all my rambo memory upgrades! So I plug my 4164's in and solder across one spot marked W1 on the motherboard. I did notice it when looking for a 64K jumper that was labeled as such, but that's on Coco 1's only apparently. So I'll have a 64K Coco 2 in about five minutes here, and I can either order a OS chip for it, or wait until I get one of my Atari's running and I can burn the OS to one of my 8K eproms on my Atari eprom burner! Maybe a reason to motivate me to get at least my 800 fixed, since it can use the burner now in XL/XE mode.

I may have to go ahead with the video mod too, and might as well while I have it open, before I'll even be able to test it. So my first test will be after installing 9 IC's and a bit of soldering and after building a small video board.

 

By the way, from what I'ved learned, thought the Coco mouse is analog just like the joysticks, for some damned reason to use it you have to get this 'Color Max' module that plugs into the cart/expansion port and it has another analog port, exactly the same as the joystick ports on the back. And there is a built in GOS environment graphic art program in the module to use with the mouse. From what I've read, it is about the only software that uses a mouse (until the Coco 3), so I'm going ahead with plans to convert it for use with my Atari's. Better graphics and art progams are on the Atari anyway. I didn't get the Coco for that. It only has a 9 color palette and can use 4-9 colors depending on graphic mode.

 

Well, I swapped out the 16K ram chips for some 41256's. I could only find 5 4164's and then remembered the rest were on the 16K 800 ram board I was modifying for 64K when I got the Incognito. It's in my glass case, difficult to get into now.

So I knew 41256's would work as 4164's and I have plenty of them too now since I reverted my 1200XL back to 64K internal since I have the PBI and an external 512K on the Syscheck board.

And since I couldn't find my RCA2Coaxil adapter, and deciding not to wait until I did a video mod, to make a hacked-together temporary RF cable to my TV. And PRESTO! I have a MINT condition 64K Coco 2 only needing the Extended Basic rom and that video mod I will do this weekend. So it was just some IC's that needed to be re-seated in their sockets!

I tell you, first controllers coming to me for free, then a deal for a not-working-right Coco 2 that looks in good condition, then find out it's in pristine condition after a good cleaning, and a perfectly pristine interior...a perfectly new working motherboard after re-seating the IC's...using the same type of ram I have on hand...an eprom burner for my Atari that can burn the ROM I need for the Coco 2...a new shop/lab/office trailer to make more room for my kit...this was no series of coincidences, this was destiny.

I'll just have to have both a Coco 1 I restore and upgrade and a mint Coco 2. If it were a well-used machine with a yellowing case like I saw many of on ebay, then I would use it as a parts machine.But this thing is in mint collector's condition with no refurb or restoration needed. So I will keep it and keep it that way. I just noticed too, that the name plate still has the protective plastic over it and I'm leaving it in place because even that plastic film has no scratches or nicks and is perfectly invisible! I only discovered it by touch myself!

My RF hack-job:

My working TRS-80 Coco 2 already upgraded to 64K, maybe 256K if I find there is a way with these IC's:

My mint condition TRS-80 Coco 2 after a good cleaning with a cloth and window cleaner:


.

 

Below are some facts and specs on the TRS-80 Color Computer 1 & 2.

_________________________________________________________________________________
The Color Computer was part of Radio Shack’s attempt to diversify their computer product line. Costing only $399.00 for its basic model, it was designed to compete with other lower-cost computers, such as the Atari 400 and the Commodore VIC-20. But the Color Computer inspired a wide range of uses, multiple support magazines, and a vibrant third-party software and hardware market. The Color Computer series was probably the best selling of Radio Shack’s own computer models.



Color Computer specs

The Color Computer used the Motorola 6809. (Early rumors said it would be called the TRS-90 because it lacked a Z80.) This was unusual because most other inexpensive computers at the time (and some expensive ones such as the Apple II) used the MOS Technology 6502. The Motorola 6809 was a highly regarded processor with many design features that were more in line with a 16-bit microprocessor. Even though the 6809 in the Color Computer ran at only 0.895 MHz, the design meant that it was comparable to the 2.03 MHz Z80 in the Model III.


Specifications

The Color Computer had good specifications for a home computer at the time:

-a Motorola 6809E processor running at 0.895 MHz
-a 53-key “chiclet” keyboard, with arrows, BREAK, and CLEAR keys
-uppercase-only text mode with 32 column by 16 lines
-eight graphics modes, including 64 by 32 with eight colors and 256 by 192 with four colors
-one RS-232 port (the so-called bitbanger port)
-sound output with a 6-bit digital-to-analog converter
-1500-baud cassette I/O for storage
-a slot for plugging in cartridges known as “Program Paks”
-initially 4k expandable to 16k then later a 32K and 64K

64K NOTE: The reason BASIC memory is the same for 32K and 64K is due to legacy designs. The 6809 processor can only address 16-bits of memory space (64K). The BASIC ROMs started in memory at $8000 (32768, the 32K halfway mark). This allowed the first 32K to be RAM for programs, and the upper 32K was for BASIC ROM, Extended BASIC ROM, Disk BASIC ROM and Program Pak ROMs. Early CoCo hackers figured out how to piggy-pack 32K RAM chips to get 64K RAM in a CoCo, but by default that RAM was “hidden” under the ROM address space. In assembly language, you could map out the ROMs and access the full 64K of RAM. But, since a BASIC program needed the BASIC ROMs, only the first 32K was available.

When 64K upgraded became available, the original BASIC would still only report about 24K free since it had never been modified to make use of the extra memory. Thus, typing “PRINT MEM” on a 32K CoCo 1 shows the same thing it does on a 512K (or greater) CoCo 3.

___________________________________________________________________________________

Back to me me talking:


After I installed my 64K, but still only standard BASIC 1.2, minus memory for cassette, serial and some other I/O, when I do a "print mem" command it shows I have about 31K available instead of the 24K available for Extended Basic 1.1! So I will lose even more Basic ram space once I install the extended Basic rom chip!
But since it show 31K available under Basic, that means it's seeing 32K ram so most likely my full 64K is working, I just need to load up a 64K machine language tape program to know for sure.

Also, it suddenly occurred to me, after reading that any standard cassette recorder could be used with the Coco series, even though they had one specifically designed for the system, that some of those cords I got with the Coco joysticks and mouse are actually a cassette cable and probably a serial cable!

 

Great discoveries being made, Matt!

I lurve how a new model on the scene sets in motion all this research and unearths nuggets of interesting information.

It always amazes me just how ingenius the hackers and modders are too and I reckon the sky will again be the limit with this Coco, mate.

Keep us posted!

 

The TRS-80 Color Computer 2 temporarily takes the place of the 800, and possibly permanently depending on how soon I run electricity to my new, essentially workshop/computer lab/office, a man-cave, as this will be a private office,etc, anyway. I go to the customer in my business, they don't come to me.

 

It's all looking Coco sweet there, Matt.

Liking the Douglas Adam area with the Hitchhikers Guide to the Galaxy Infocom adventure bits too.

So much to interest the retro computer enthusiast and mine's filling fast too.

Just a shame we're so distant else a visit to view, chat & discuss would be a must!

Never mind, sending pics and talking on here is the next best thing.

Keep on enjoying your passion, fellas.

As ever, great to see the collection continue and the joy spread.

 

I decided to go ahead and move the 800 and move in the Coco 2. At the moment the 800 is disassembled inside the case anyway and if I finish the job, I'll just set it up temporarily where my 1200XL is and just use it's peripherals until the 800 is moved to the office trailer or the 1200XL is fixed.

So here is a proper Coco 2 setup, including a tape recorder with cable to the Coco, Coco mouse and Coco joystick, connected to a 14" CRT TV I dug out of storage (salvage from a customer junk-haul off job-I wasn't using it for my Atari's as they are PAL not NTSC) that is grey metallic color and will match the Coco 1 and peripherals when I get it. Unfortunately I don't have a remote for this CRT TV and it seems to be stuck in AV mode and I can't get it to change to RF channels, the channel buttons do noting unless I press the menu button and nothing in there to change channel off of AV mode! So I'm still going to have to do composite video mods to my Coco's before I can use this TV, unless I find a remote or some other way via the TV buttons!

All those cables I got with the Coco joysticks and mouse that I guessed were for MIDI, are actually 5 TRS-80 Coco tape drive cables! And one cable that had an Atari style 9-pin joystick plug on it and audio style mini jacks at the other end, like the Coco tape cable, is also a tape drive cable, I found out, but for a Texas Instruments TI-99/4A and another grey cable that looks like it has Coco style plugs on it, is in fact a monitor cable for a TI-99/4A!

 

Looking good there in the command center, Matt.

The mystery of all those obscure leads is now solved and the previous owner was one time fan of Coco and Ti-99 gear then?

Know what you mean about irritable snags with CRTs.

I have 3-4 (at least) either kicking around in the attic or garage (we always need a spare or 3 don't we?) and every single one has SOMETHING wrong with it.

I kinda recognise the styling of yours and if I do come across any spare remotes I'll let you know.

What make/model is it out of interest?

Nice work continuing to restore, mod and expand your impressive collection, Matt.

 

Did I mention that the "melted" keyboard of my Coco 2 feels nearly identical to the touch and travel distance of the Atari XE computers "mushy" keyboards? Keyboard nostalgia without the XE!

But at least it will still be an upgrade to the chiclet keyboard of the Coco 1 when I get it, and I do think the look fits the Coco 1 better than using a Coco 2 for 3 full-travel keyboards on it.

Also, by the way, the cheap, wireless $10 PC keyboard I am using right now, with full-size chiclet keys, feels like the XE and Coco 2 melted keyboards in the "mushy" feel and travel distance too. I'm used to both mushy and fantastic feeling keyboards between my Coco/PC and 1200/800.

Of course I have better PC keyboards I could use, but they have cables and are less convenient atm.

 

The brand is Durabrand. I found out it's made in China, the rear sticker is all there with manufacture date of June 2005 (I thought they stopped selling CRT's before 2K5!?) and model number BH13040D.

I found and purchased a remote for it on eBay, with free shipping for less than $10. Actually, I need to go see about buying one for that 23" CRT I have now too, though I can change video modes without a remote with it. But if I can fine one for it for less than $10 I'll buy it too.

 

Excellent, Matt. Well sourced, mate.

I would have thought CRTs would have stopped being produced sometime late 90s/very early 2000s but there you go!

 

I found the remote for my other 23-25" Sanyo CRT too, for even less than the Durabrand.

While I was on eBay, I also bought a couple of Avalon Hill games, NIB, one for less than $20 and the other for $25. One is VC, a Vietnam strategy war game, and the other, Conflict 2500, a strategy game on a galactic war scale. As some may remember, I've been on a quest to collect strategy war games, and also any games from the companies that used the heavy cardboard boxes with similar construction to board games. As Avalon Hill and SSI and Epyx and Origin did.

I had remembered when looking through specifically Avalon Hill games for sale in the past, that many of them, especially the cassette tape versions, had versions of the program for several micros on the tape. I double-checked my Legionnaire and Telengard A.H. games, but they are Atari specific. But I made sure the games I bought this time, in light of my new TRS-80 Color Computer, that I bought A.H. games that included versions for both the Atari and TRS-80 Coco's. VC and Conflict 2500 do. That way I'll have a couple commercial games for the Coco to play soon, though I am learning to record Coco tape game .wav files back on to cassette in the mean time.

I've also ordered an upgrade board for the Coco 2 to allow 28-pin eprom to work through the Coco's 24-pin Extended Basic rom socket (24-pin versions of the rom are ultra rare)so I can burn that on a 2764 eprom using my Atari and the XL/XE eprom burner.

I also found out that there is a newer revision of the 6809E processor in the Coco that works better and has added abilities but still 100% pin-compatible.

Also a new MMU board that goes in the 6809's socket and the the 6809 plugs into it, and this new memory unit, along with upgraded ram (separate upgrade), allows Coco 1 & 2 to run the Coco 3's OS/9 multi-tasking OS! The only caveat is the Coco 1 or 2 with these upgrades will still not be able to run any Coco 3 OS/9 software that uses the Coco 3's new graphic modes they don't have. But lot's of Coco 3 software will run, except mostly games which is what uses the new graphics mostly.

Another new discovery is that with the last revision of the Coco 2, they put in a new VDC chip, the chip that handles Coco's graphic and text modes and this new chip has the lower case text abilities that the original didn't have. I can upgrade to it too.

And more...though not as much new hardware as we have for Atari 8-bits. There is an SD card drive, and something like SIO2PC/APE and adding additional new sound chips, like Pokeymax does, with YM and Covox and DAC, but on the Coco they are boards that plug into the cart/expansion port (basically the Coco's PBI/ECI port) instead of internally. And more...

 

What can I add, fella?

I'm a big big box wargame and strategy collector too as I just adore all that graphic art, bumpf and paperwork you get inside which helps to set the scene in the player's imagination.

The fact you're getting Atari and TRS versions on the same tape is indeed a double bonus, Matt.

Some great explorations you're enjoying with this new set-up, mate.

The sky's literally the only limit with some of this retro kit.

 

Continuing my research and learning what devices and peripherals the Coco's had legacy wise, and modern home-brew, One thing I've learned is the TRS-80 Color Computer (line) is a strange beast. It's modular, like Atari 8-bit and Commodore Vic-20/C64 computer lines, So one can buy the basic computer and add on via peripherals and other devices. But it's architecture is more like the Apple II line, with dumb peripherals that required controller cards, but since it's modular, it's more like the TI-99/4A with it's expansion box or the proto-type Atari 1090 PBI expansion box.

But not quite, as it's not done with internal cards like and Apple II or the other's expansion boxes, it's done externally, through the TRS-80 Coco's expansion/cartridge port (similar the PBI/ECI/Cart ports on Atari 8-bits) with a multi-pack device, with four external "cartridge" positions for you to plug in your floppy or hard disk controller, or modem/RS232 pack, other port expansion like centronics parallel adapter module. And controller packs came with just about every device like graphics tablets or high-resolution mouse adapter packs.

You end up with a bulky monstrosity with huge "paks" sticking up out of the multi-pack device right on the side of the comoputer, and any serious user would still have more peripherals controllers and cartridges than the 4 slots, so power-downs, swapping, and restarts had to occur.




There was a model for every model of Coco, and even some after-market ones with up to 6 ports.



"pack modules" are huge bulky things, like two 5200 cartridges stacked.



I much prefer Atari's smart peripherals and the SIO, honestly, with the occasional PBI/ECI device.

The Coco's 6809 CPU runs at less than 1Mhz, and even with advanced features usually only found in 16-bit CPU's, because of it's 0.8xx clock rate it's hardly better than the 1Mhz original 6502 in the ViC-20. They say it compares to a 2Mhz Z80, but I also know that the Atari's 1.77/1.79Mhz 65co2 compares to the 4Mhz Z80 in the Coleco Adam, so that tells me it's exactly what it seems, a CPU half about half the speed of the Atari's.

Though with the last model of Coco 2 a newer version of the 6809 was used and had an undocumented "turbo" mode that can be poked to put the CPU into 1.78Mhz mode.

The Coco's VDG (video display Generator) is closer in ability to the VIC-20's VIC I chip than the VIC-II or Antic. Again, in the last model revision of the Coco 2, a slightly upgraded version included lower-case text that Coco's before didn't have. But it still only produced 32-column x 16 line text screens. It has nearly as many graphic modes as the Atari. Bitmap mode included a 9-color palette, but only the lowest resolution could display all 9 colors. the other modes were limited to 2-4. It's high-res mode, like the Apple II and Atari's used artifact colors, but the Coco could only do orange, blue, black and white, while the Apple II and Atari's NTSC artifacting can achieve 8-9 colors..

Resolution graphics store 8 pixels per byte and are available in 128×64, 128×96, 128×192, and 256×192 modes. Color graphics have 4 pixels per byte and are available in 64×64, 128×64, 128×96, and 128×192. The maximum size of a bitmap screen is 6144.

The Color computer has two PIA's (like the upgrade I just did to my 800!) that control all I/O through the cassette. Serial (RS232) and worked with a simple ADC/DAC 6-bit chip for that analog joystick ports and keyboard. Unfortunately the Coco didn't have the advantage of a dedicated chip like Pokey for keyboard and high-resolution analog pots, so the Coco's joysticks and mouse, with the 6-bit chip, only had a resolution of 64x64!

This was fine for games and using the mouse or joystick to move a cursor around a 32x16 screen for programming or word processing (who'd want to do 32-column word processing with only upper case text anyway? Lower case was represented by inverse video). So high-resolution control packs were required for the otherwise perfectly good mouse and joystick to be used to their full potential. You then plugged them into a new port on the control pak! But only a high-res graphic art program with artifact colors took advantage of this before the Coco 3.

I certainly don't plan to do art on my Coco 2 with it's color limits, so I am going to convert the mouse for use with the Atari 800. I still have analog joystick just as sensitive to move the cursor around on-screen with the Coco anyway.

Coco sound chip? Terrible. yet another use of the expansion port was an Orchastra-90 pak with a better sound chip.

Of course these days there are plenty of internal and external upgrades for the Coco line including a VGA board for VGA output that includes new graphic and text modes (64 or 80 column), sort of like a cross between the VBXE and Sophia 2 on the Atari. Memory and speed upgrades and OS too. So there is plenty for me to mod and upgrade and bring this Color Computer 2 of mine up to par with Atari's and all their cool modern upgrades.Unfortunately, while modern upgrade hardware on the Coco line is on pace with the Atari's, the home-brew software side is absolutely dismal and little takes advantage of the new hardware, as the few home-brew games that have come out, want to reach the lowest common denominator and go unused, like the VBXE. But even so, new games since the 80's can be counted on both your hands for the Coco line, it seems,