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Commodore Colt (PC10-III/PC20-III)

K

KenEG

Experienced Member
Joined
Oct 20, 2016
Messages
440
Location
Cincinnati, Ohio USA
I watch eBay for these because it was my first IBM compatible computer. I saw one for $139 and noticed it was listed as having a standard IDE port. I wrote to tell the seller that this was an error, I had no intention to buy it. He thanked me and asked if I was interested. I told him I could only offer $80, because I would want to add VGA and sound cards and a keyboard. This would make the total price up beyond what I was willing to pay. Plus I would be taking a chance on motherboard damage from a leaking battery. He put a Sound Blaster CT2910 and a Mach32 in it, provided a photo showing minimal damage from the battery and offered it for $100, free shipping. At that point, how could I refuse? I got it a couple of weeks ago and verified that it booted.

Tonight I removed the battery and cleaned the motherboard. There truly was little to no damage. I soldered in wires and have a wireless phone battery installed on the inside of the front, plastic case. Put it back together and verified that it boots. I have downloaded the disk images for the computer, making the disks will be a project for another day. I also bought a Seagate ST351A/X 43MB hard drive for $45.95 that is supposed to be tested working. Depending on my BIOS version, it may only be usable in 20MB mode. That was all mine had anyhow and maybe I can upgrade the BIOS later.

I have been reading about this computer and certainly didn't appreciate how nice it was when I had the original. I am using it with an XT keyboard for now. I hope to acquire the correct keyboard some day, if I can get one at a reasonable price.

I will post more as this project progresses.
 
Never got help, didn't give it much time, but reread the wiki and got it going. Read my posts on the other thread if you want details. One thing I discovered while researching is that the internet has two versions of how the jumpers run. Numbered back to front or front to back. Mine run front to back. The drive uses jumper block smaller than normal. I cold use one more than I have. Any ideas where I can get them?

I have IBM DOS 3.30 on it now. I will probably put the original files on it once I create the disks. I want this computer to be as much like the one I had years ago as I can remember to make it. More to come ....
 
The PC10-III is a wonderful computer. You can also use an Amiga mouse with it, leaving the serial port open for other uses. My PC10-III had some damage around the clock area because of a battery failure.

Here's mine:
http://www.amibay.com/showthread.php?64820-My-Commodore-PC10-III-Project

My only complaint with the system is the low number of expansion slots. :)

Good luck with yours! I'm using the XT-IDE because of the limitations of the internal IDE controller and it gives some nice extra features.

Heather
 
SkydivinGirl said:
My only complaint with the system is the low number of expansion slots. :)
Click to expand...

Yea, if you look at the back of the case, you think "hmm, 4 slots", but then you open it up, and find that one of them is just a dummy, and there's only 3 connectors on the board :/
I have a PC20-III with the original XT-IDE drive of 20 MB, and it still works.
I never actually bothered to check how the battery is doing, because I totally forgot it has one.

I used to have a PC10-III back in the late 80s, as my first PC, also installed a Seagate ST351 A/X in there, which worked as 40 MB in mine... funny enough that drive was actually the stock drive of the PC I upgraded to: the Commodore 386SX-16. Once I upgraded that machine to a 170 MB drive, I tried the Seagate in the PC10-III, and it worked fine.
Before that, my PC10-III was upgraded with a 20 MB Kalok with its own MFM controller card. Because of a misconfiguration it was formatted with too many sectors per track by the shop that installed it, so it actually worked as a 30 MB drive. It worked remarkably well considering the misconfiguration, but we were always plagued by random read errors.
The ST351 solved that once and for all.
 
SkydivinGirl said:
The PC10-III is a wonderful computer. You can also use an Amiga mouse with it, leaving the serial port open for other uses. My PC10-III had some damage around the clock area because of a battery failure.

Here's mine:
http://www.amibay.com/showthread.php?64820-My-Commodore-PC10-III-Project

My only complaint with the system is the low number of expansion slots. :)

Good luck with yours! I'm using the XT-IDE because of the limitations of the internal IDE controller and it gives some nice extra features.

Heather
Click to expand...

I used a lot of the information in your amibay post to get as far as I have! It was very helpful. The only thing I've found different so far is that mine seems to be Y2K compliant. That was a very cool discovery this morning when I was testing the RTC after installing the original MS-DOS 3.21 with the setclock and speed utilities. I may some day try an XT-IDE set as a secondary controller. For now, I am trying to recreate the one I used to own. I am pretty close now.
 
I'm glad the post was helpful! :D

I'm going to replace the RTC chip in mine with a compatible one I found. I'm hoping that will fix the extreme drain on the replacement clock batteries I've tried in the past. It will also make the machine Y2K compliant. :)

Good luck with your build! I hope you are able to get it to the same condition as your old one.

Heather
 
More adventures with it today. I found a jumper block and got the hard drive light working. Then I tried loading a game -King's Quest IV. The install would freeze. Tried another game King's Bounty. Would freeze also. Thought maybe the Mach 32 card wasn't 8 bit compatible. Tried two other cards, one pulled from my other XT-Turbo machine where I know both games work. Still no go. Changed setting of onboard video from color 80 to monochrome. Games worked. Put the video 7 card I took from my 386 machine in it. Still works. Decided to leave the Mach 32 card in the 386 because I think it is a better card than the Video 7. KB only uses PC speaker, but KQ4 uses the Adlib part of the Soundblaster 16, so it is working also. Testing of the SB functionality can come later. I spent several hours today getting to this point, but it was worth it. I think I only had an Adlib in mine anyhow. My first Soundblaster came later.
 
SkydivinGirl said:
I'm glad the post was helpful! :D

I'm going to replace the RTC chip in mine with a compatible one I found. I'm hoping that will fix the extreme drain on the replacement clock batteries I've tried in the past. It will also make the machine Y2K compliant. :)

Good luck with your build! I hope you are able to get it to the same condition as your old one.

Heather
Click to expand...

You might want to try what I do. I buy a 600 mAh 3.6v cordless phone battery. I solder long wires to where the battery went and run them to a safe location. If you use the right size solid wire, the bared ends plug right into the connector on the battery. I used a 3M sticky thing to attach it to the front case of the Colt in the area where the hard drive goes. This is the second computer I have tried this with and it seems to work well. You get 600 mAh vs the 60 for the original battery, so it should last good between uses of the computer.
 
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KenEG said:
You might want to try what I do. I buy a 600 ah 3.6v cordless phone battery. I solder long wires to where the battery went and run them to a safe location. If you use the right size solid wire, the bared ends plug right into the connector on the battery. I used a 3M sticky thing to attach it to the front case of the Colt in the area where the hard drive goes. This is the second computer I have tried this with and it seems to work well. You get 600 ah vs the 60 for the original battery, so it should last good between uses of the computer.
Click to expand...
mAh, not ah. :)
 
KenEG said:
Changed setting of onboard video from color 80 to monochrome.
Click to expand...
Yes, I also found that you have to set the onboard video card to Monochrome if you are using an ISA video card in the system. That may even be in the manual but I'd have to double check.

KenEG said:
You might want to try what I do. I buy a 600 mah 3.6v cordless phone battery.
Click to expand...
I've tried CR2032 and big battery packs. The big battery pack lasts a couple months, but it's still being drained very fast. I'll socket the clock chip and try the new one. Having one that has the Y2K fix will be nice anyways since the script I wrote slows down the boot process by a few seconds.

Heather
 
SkydivinGirl said:
Yes, I also found that you have to set the onboard video card to Monochrome if you are using an ISA video card in the system. That may even be in the manual but I'd have to double check.
Click to expand...

Actually, I think there is a better way.
If you set the video card to monochrome, it is still active as an MDA/Hercules adapter (which might be what you want, if you go for a dual monitor setup, if you type 'mode mono', DOS will switch its output to the MDA/Hercules output).
If you have a VGA card that can also emulate MDA/Hercules, then this mode cannot be used.

But if you set all dipswitches down instead of up, it is actually entirely disabled, and your VGA card can be used fully.
This is what I use.

It is standard PC behaviour by the way that an MDA/Hercules card and CGA/EGA/VGA card can be used together. That is why switching the onboard to monochrome makes a CGA/EGA/VGA card in an ISA slot work. If you would put an MDA/Hercules card in an ISA slot, you'd need to switch the onboard to COLOR.
 
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Yes, I knew I had seen how to disable the onboard video somewhere. I looked at the wiki again last night and turned switches 3 and 4 down. It is nice to know how to use monochrome mode with the VGA though in case I ever want to try it. I have never had a computer that only used monochrome. Coming from a VIC-20 and then a C128, I always wanted color.
 
I played King's Bounty for a couple of hours today. The system seems to be stable. Also, I had trouble getting it to run on my other XT. The Colt seems to be more compatible. I also discovered the keyboard that I was using with my 386 with an AT to PS2 adapter has an XT AT switch. Works great on the Colt. I have PS2 keyboards.
 
SkydivinGirl said:
The PC10-III is a wonderful computer. You can also use an Amiga mouse with it, leaving the serial port open for other uses.
Click to expand...

That's pretty cool. Atari did a similar thing with their XT clones in that they came with a mouse called the PCM1 which was just a rebadged STM1 from the Atari ST with a different tone grey. I thought it was something unique to Atari but it seems I was wrong.

Was it ever the case that they bundled with the PC10-III or was this just an optional feature?
 
Flamin Joe said:
Was it ever the case that they bundled with the PC10-III or was this just an optional feature?
Click to expand...

I don't think they did. The mouse wasn't a very popular item back then. Windows wasn't 'a thing' yet, and most DOS applications didn't support it.
Silly enough, we didn't know this when we bought our first mouse, so we bought a Genius serial mouse, instead of an Amiga mouse.
When I got an Amiga later, I tried its mouse, on the PC10-III and found that it worked great.
 
Yes, I bought my Colt new. It didn't come with a mouse and I don't think I ever had one until I got my first Windows 3.1 machine. Just not very useful in that era.
 
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