Skip navigation

colt1

Commodore is best known for thier unique series of home computers such as the VIC-20, Amiga, PET and best selling Commodore 64 but like all PC manufactures in the the earlier years Commodore had its tentacles in the world of PC clones as well. One such PC clone (or more specifically turbo XT clone) from Commodore was the Commodore Colt which is a rebranded Commodore PC10-III. Maybe a group of executives figured a cool name slapped onto a new case would move more units then the boring and business sounding  PC10-III. From what I can find the PC10-III was launched in 1987 and used the exact same motherboard as the Colt and only the case and name were different. The PC20-III also used the exact same motherboard and was merely a PC10-III with a factory installed 20MB hard drive. From the rest of this article on when I refer to the Colt the same things apply to the PC10 and PC20 III’s. Despite being a PC clone machine the Colt has a number of unique quirks and features giving the machine a personality of its own.

colt2

I found my machine as far as I could tell completely factory stock and in great physical and working condition. The front of the PC has a Commodore logo and badge as well as activity lights for a hard drive and power. There is no power button on this machine or reset button so powering on and off is done via a switch on the back which admittedly is a bit of an inconvenience. There are two half height 5.25 drive bays. The Colt came stock with either one or duel 360K drives like mine does. both of my drives thankfully worked perfect.

colt3

The keyboard port is not located on the rear of the machine but on the right side of the case. The mouse port on the Colt is for a 9 pin D-sub bus mouse port and is compatible with the 1352 mouse which happens to be the same mouse used with the Amiga. This appears to the system as a bus mouse and standard MOUSE.COM drivers in DOS should work just fine. Next is the built in Video which uses a composite out jack for a composite monitor and a 9 pin video port for CGA via the onboard Paradise PVC4 chip. There are a few DIP switches next to the video port to set the video along with an extremely handy chart on what the settings are which was good thinking on Commodores part. Next is a 25 pin serial port and finally a printer port. There are a measly four expansion card ports but even worse the motherboard itself only has three ISA slots which we will see in a minute. Powering all this is a proprietary form factor 75 watt power supply.

Here is a quick look at the green screen monochrome monitor that came with my Colt. The picture quality was very good and this monitor was very light.

coltm1

coltm2

The Colt case is fairly easy to remove after a few screws are removed.

colt4

Now that the case is off we can see there is room for an internal drive which is slightly uncommon for an XT class machine as usually the case expects you to be mounting a half height MFM drive in one of the 5.25 inch bays though will get our explanation for this as we open up the case more.  Another thing we can notice is the lack of expansion ports. The Colt sports only three 8-bit ISA slots which is about the smallest I’ve seen for a machine of this form factor. This deficiency is somewhat made up for though with the multitude of good quality built in features like the quality CGA video and built in floppy controller.

colt5

Here is the exposed motherboard. You can see the keyboard port on the bottom of the image. The board itself is overall pretty well made and compact.

1) CPU – The Colt uses an 8088-1 CPU capable of 10mhz speeds. The really cool thing about the Colt is that its Faraday FE2010 chipset allows the CPU speed to be adjustable via a SPEED.EXE utility via DOS or through keyboard commands. The default is the standard 4.77mhz but the speed is adjustable to 7.16mhz and 9.54mhz

  • CTRL+ALT+S switches the CPU to the “Standard” 4.77MHz speed
  • CTRL+ALT+T switches the CPU to the “Turbo” 7.16MHz speed
  • CTRL+ALT+D switches the CPU to the “Double” 9.54MHz speed

This is a really nice feature that helps give a boost to programs that need it and giving the best compatibility. Most machines I’ve encountered have only offer two speed settings, usually 4.77mhz and 7.16mhz. The Colt like almost all 8088 machines can be upgraded via an NEC V20 CPU giving a significant speed boost at the slight cost of game and program compatibility.

colt6

2) NPU – This is the math co-processor slot if one should choose to add an 8087. This obviously gives a boost to programs which use the extra math power of the processor though almost no games of the era use this feature. If adding a math co-pro be sure its the 8087-1 variety that is capable of 10mhz else you may encounter instability if running the machine at 9.54mhz “double” speed.

3) RAM – The Colt comes with a full 640k of memory on-board which is the full amount a XT PC can address and more then enough for the CGA era. More RAM can be added via expansion cards but like the math co-pro nothing this early takes advantage of the extra memory and it’s really a waste of the few ISA slots this machine does have.

4) PSU – This is the proprietary power connector for the power supply which can present a problem if your Colt’s power supply is dead or dies. A standard AT power supply, provided it fits could possibly be modified to work.

5) Video – The onboard video features the Paradise PVC4 which functions pretty much just like an ATI small wonder CGA card. The layout is actually the same as on the small wonder cards and  it could be that Paradise produced the actual chips for the small wonder cards but I haven’t been able to confirm this. The onboard video offers the same modes as the small wonder cards by outputting CGA composite via the RCA jack as well as MDA, CGA Color text and graphics, Hercules monochrome, Plantronics Colorplus and Alpha132 Monochrome via the 9 pin video port. This is one of the few times I didn’t upgrade the video in a PC since the go to card for me on an 8088 would be a ATI small wonder CGA card but in this case it wouldn’t offer any benefit over the onboard video and would eat one of the precious three ISA slots.

colt7

6) XTA interface for hard drive – Now this is a very interesting feature of the Colt and probably why we see a small internal bay for a 3.5 inch hard drive. At first glance the connector next to the floppy drive interface may look like a more modern IDE connector but it’s actually an 8-bit variant known as XT or XTA IDE. The connector looks the same as IDE and should fit the same cables but unlike the 16-bit variety we are used to seeing this short lived 8-bit IDE standard will only work with a very small number of drives. There may only be about twelve or so models built to work with this standard and they are all old, unreliable, small in size (20mb or under), hard to source and probably massively overpriced. As neat as it is having built in IDE on a 8088 machine, due to the factors I’ve already stated it’s best to disable the onboard  interface via jumper JMP208 and seek out a controller card instead.

colt8

7) Floppy drive interface – This is the built in drive interface. The floppy controller on the Colt cannot be disabled to allow for a separate card to be used and this controller does operate differently then a standard controller. It supports 360k drives which is usually what the Colt came stock with but it also supports 720k drives. Adding a 720k drive can be a difficult task and the process is a little more involved then in other XT clone machines. If you’d like to learn about this scroll down to my upgrade section where I will be covering this.

8) Speaker – unfortunately the Colt does not feature an actual cone PC speaker but instead a piezo beeper speaker

I want to go over a few upgrades I did with my machine that I think make it a better all around PC to work with giving me more flexibility and an overall improved experience.

The operating system I have installed on my machine is MS DOS 3.2 which is the original OS distributed with the Colt.

UPGRADES

CPU – The first question I had with the Colt was whether I wanted to replace the 8088 CPU with a NEC V20. As I’ve said in just about every 8088 review I’ve done the NEC V20 upgrade is generally recommended and offers a speed increase (up to 15%) at only the cost of slight compatibility with a few very speed sensitive games and programs. For my Colt though I decided to stick with the 8088-1 for full compatibility speed wise with the CGA games I plan on playing on this machine. I also installed a Intel 8087-1 math co-pro though it will likely see little usage.

Hard Drive – for the hard drive I used the Silicon Valley APD50L  8-bit hard disk controller that I previously had installed in my Epson Equity E1 PC. This card should give slightly better performance than a IDE-XT card. I ended up pairing it with a industrial grade 32MB CF card. I generally do not use CF cards with most of my systems but I felt it really benefited here with its speed and much lower power draw. My Colt fortunately came with its original working floppy disks so I was able to install MS DOS 3.2 with the Commodore SPEED utility. 32mb is also the max size partition limit for DOS 3.2 which I think is far more then enough space seeing as I will be using this machine with early 80’s games and most programs of the time  are very small.

colt9

Sound – Since sound cards didn’t become a thing until the late 80’s a sound card in an early 8088 based XT machine is far from necessary. Pretty much everything you can run is going to be PC speaker only. Seeing as this was going to be my new all around XT PC though I wanted the option in case I wanted to play something like a demo or something like Prince of Persia in CGA mode. To that end I installed a Sound Blaster 1.5. The 1.5 is an 8-bit Sound Blaster card which is identical to the SB 1.0 except that the Creative Music System compatibility was dropped. Thankfully this can be restored giving high CMS compatibility by adding two cheap Phillips SAA-1099s into the two empty sockets. This is much easier to achieve then with the later SB 2.0 which also requires a hard to find GAL chip. I like the sound blaster because it gives me Adlib, CMS and SB support if I so choose.

colt10

Adding a 720k floppy drive

colt12

now I’m going to make this a section of its own since as I stated earlier the process is a little more involved on a Colt then a regular XT clone. Although the onboard controller does indeed support 720k drives how it goes about this is different. First off I wanted to keep my drive A: as a 5.25 drive since this is the primary format of the era and most of the PC booter games I have are this format of which many require the booting drive to be A:\. Before I go any further I also want to thank the good people over at the Vintage Computer Forums and especially Scali and SkydivingGirl for helping the retro community figure this process out as it was not well documented at the time.

You may notice that the floppy drive cable that came with your machine lacks a twist found in most other floppy cables to help the machine differentiate drive A from B. The Colt instead uses jumpers on the floppy drives themselves to make this distinction (DS0 for A: and DS1 for B:). Note that using a standard cable with a twist will NOT solve this issue as the motor on signal to the floppy is also done differently at best only one drive will work.

colt13Original cable with two 5.25 floppy edge connector

First off I have only done this with the original Chinon FZ-502 5.25 drive as drive A: so I’m not sure how it would perform with a 3.5 drive not being B:. make sure your 5.25 drive is jumpered as DS0 and leave everything else as default.

Next your going to need a 5.25 to 3.5 inch bay converter so your 720k drive will fit in the 5.25 inch bay. For simplicity I also acquired a 34 pin to edge connector converter like the one below so I wouldn’t need to mess around with a different cable. I acquired mine at http://www.bgmicro.com/

colt15

 Lastly your going to need a 720k drive with jumpers. I went with a Chinon FZ-357 drive but I can confirm a Chinon FZ-354 also works in 720k mode as well as a Gotek SFRM72-FU-DL 720K floppy emulator . The jumpers on drive B: need to set very specifically for it to work. Make sure you close the DS1, MD, DC, and TTL/C-MOS jumpers as below.

colt14

If done correctly you should now have a fully working 720k floppy drive in your Colt or PC10/20-III PC.

 

Adding an XTA hard drive

As stated earlier, if you want to use the onboard XTA hard drive interface your going to be very limited on what drives you can use. Possibly the best choice is the Seagate ST-351A/X drive.

colthdd1

First off remember to set the onboard jumper JMP208 to enable the onboard interface. make sure its jumpered to the pins that are in line with the other jumpers beside it. If you have an early BIOS revision of 4.35 like mine your going to be limited to 20mb of space at most.  With the ST-351A/X  you must set the drive to XT mode. My drive is jumpered in the following way.

colthdd2

After the drive is jumpered and attached correctly you should not get a “hard drive not found” message on the boot BIOS screen anymore. Theres a few more steps though from this point.

Boot the PC from a floppy disk and when you get to the A:\ prompt run DEBUG.EXE.  which will take you to a “” at the prompt type G=FA00:5 and press enter. hit enter for the next to questions that come up. When asked about dynamically configuring choose N and lastly hit Y to begin low level formatting.

If everything is set up ok and the drive is in working order the program should low level format your drive. After a reboot you need to run the FDISK program to set a partition. after setting a partition use the FORMAT command. type FORMAT C: /V/S which should be the final step to allow you to boot from and use your hard drive.

colthdd3

colt16

Overall the Colt is a nice looking, reliable and compact XT clone. Its hampered by its lack of expansion slots but this issue is mitigated somewhat by the quality onboard options. The three CPU speeds are probably one of the neatest features I’ve seen in any XT class machine and I love the flexibility it affords me. The hassle with adding 720k floppies does detract from the usefulness of the Colt plus the virtual uselessness of the built in XTA hard drive interface makes the option pointless for the most part. They are neat machines and with a little effort can be made into very competent 8088 XT PC’s but in honesty unless your a die hard Commodore fan like myself, crave the coolness factor or stumble across a working one for super cheap its probably not worth the hassle. A generic XT PC can be had easier without the odd floppy issues and with far more expansion card possibilities.

This slideshow requires JavaScript.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Waltorious Writes About Games

Game-related ramblings.

NekoJonez's Gaming Blog

Thank you for your visit!

Old School Game Blog

Amiga enthusiasm, retro gaming passion

Evelynn Star

Lynn talks about video games, records and books ...

Retro Megabit

Sharing My Retro Video Game Collection.

133MHz's Junk Box

Random electronics and gaming crap

SNES A Day

Every game, every day

Too Many Games

A blog talking about games

Retrocosm's Vintage Computing, Tech & Scale RC Blog

Random mutterings on retro computing, old technology, some new, plus radio controlled scale modelling.

The PewPew Diaries.

Work(s) in Progress!

The Martian Oddity

Video Games and other weird stuff!

1001Up

1001 video games and beyond

retro computing and gaming plus a little more

sparcie

retro computers and stuff

jispylicious

Stay Jispy!

lazygamereviews

MS-DOS game reviews, retro ramblings and more...

%d bloggers like this: