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The IBM AT also known as the IBM 5170 is IBM’s follow up to the IBM PC and IBM XT (and XT-286) home computer. Released in 1984 the 5170 featured a 286 processor and the then new 16-bit ISA expansion slots which would continue to be seen on computer motherboards all the way until the early 2000’s. The AT also supported high density floppy drives, came standard with a hard drive, featured a battery to store system settings as opposed to motherboard switches and was a great machine for then then new EGA graphics standard.

For the duration of this article please take not I will be using the terms 5170 and AT interchangeably to refer to this PC.

The IBM 5170 has a pretty utilitarian look in my opinion but there are many fans of the industrial look of this very sturdy case. My case was rescued from a garage and has some significant rust and scratching but it still fully functional. On the far left we have the standard IBM model badge as well as a lock and LEDs for power and hard drive activity.

On the right side of the case are dual 5 1/4 drive bays. These bays are usually populated by two 1.2MB 5 1/4 inch floppy drives though it’s fairly common to see at least one bay housing a 3 1/2 inch floppy drive via a bay adaptor. All 5170’s support 720KB floppy drives but later revisions like mine also support 1.44MB 3 1/2 drives. I did upgrade one of my 1.2MB floppy drives to a 1.44MB drive but keep in mind you will need a bay adaptor as well as a molex to floppy power adaptor.

Below these duals bays there is also a smaller bay obscured by the front panel that could possibly mount a smaller half height form factor hard drive.

Like the earlier IBM computers the AT power switch is a large red flip switch located towards the rear of the case and on the side.

Looking at the rear we see the power supply on the left side. The AT came with a PSU of about 200w which was sufficient to power a hard drive and several expansion cards and drives. The only built in port on the AT is the AT keyboard port located next to the expansion slots. The AT like the XT supports the now standard eight expansion ports which meant now you had to sacrifice less when picking and choosing expansion cards as the earlier PC only have five expansion slots.

After the five rear screws securing the case cover are removed we can take off the top and have a look inside the AT.

As seen in the image above my original configuration included three expansion cards such as the hard drive controller as well as a serial/parallel port card and lastly a cirrus logic VGA card. The VGA card will be replaced later for something more period correct for the 5170.

Below is a view of the motherboard with the expansion cards removed.

The hard drive is housed in a bay next to the dual 5 1/4 bays. The 5170 shipped stock with an unreliable 20MB MFM hard drive though at some point my AT was upgraded to a 40MB model.

The 5170 lacks any switch blocks on the motherboard and setup is accomplished via a setup program run from a floppy disk. There is an official IBM setup program but it can be a little outdated and the setup program itself may not have options for things such as 1.44MB floppy drives even though the motherboard may be fully capable. A good alternative is a program called GSETUP which you can use with the IBM 5170 as well as other computers which require setup programs.

1 ) CPU – Early versions of the IBM 5170 used a 6MHz 80286 for it’s CPU but later revisions like the one I have pictured were upgraded to an 8MHz 80286.

Even at 8MHz the AT’s 286 processor is on the slow side as far as 286 CPU’s go. It’s certainly faster then an 8088, even at 10MHz but it’s still to slow to be optimal for many VGA titles that are more action oriented like combat flight simulators. The earlier IBM XT-286 was said to run faster with the same speed CPU due to 0 wait states though I have never personally tested this.

2 ) FPU – The 5170 motherboard does have a socket for adding a 287 math co-processor to assist in more complicated mathematical processing.

The FPU is useful for CAD type programs but it’s usefulness in games is quite limited with only a scarce few games of the time taking advantage of the processors capabilities.

3 ) RAM – All IBM AT’s came standard with 512KB of memory on the motherboard. The 5170 supports up to 16MB of memory though expanding to a full 640KB and beyond does require a memory expansion card.

4 ) Battery – The 5170 motherboard does not have any CMOS battery on the board to save settings nor switches (besides for monitor selection) thus a working battery is essential to save the settings set with the previously mentioned setup programs. The 5170 in order to save settings uses an external battery.

As original batteries are long dead for the most part buying a newer replacement will most likely be required. There are many options on eBay that use AA batteries though usually the wiring is keyed differently. Modification will most likely be required as most of these battery holders are not wired for the AT.

There is a switch between the power connector and the external battery connector. This switch is for selecting the monitor in use. The rear position is for using an MDA monitor and the forward position is for CGA. The position has no effect when using an EGA or VGA video card.

5 ) AT Power Connector

6 ) PC Speaker – The 5170 has a fairly decent PC speaker located at the front of the case.

Let’s take a look at the expansion cards I have installed in my IBM 5170 making it a late 1980’s configuration.

We will start with the two cards my PC had preinstalled and not counting the VGA card I initially installed for testing.

Hard drive controller

I believe this WD based 16-bit MFM controller card which came with my 5170 is the stock card provided for the later revision 8MHz AT’s.

The other card that came with my 5170 was a simple serial/parallel port card which is extremely useful seeing as there are no built in I/O ports.

And now to take a look at the expansion cards I decided to add.

Joystick Card

I decided to add a gameport card since my soundcard of choice did not have a gameport on it as many later sound cards do.

The card I went with was an 8-bit CH Gamecard III automatic. I didn’t have any specific reasons for choosing this card other then it’s what I had on hand although it is nice that it supports two gamepads.

RAM Expansion

Having memory over 640KB isn’t to important on an IBM AT since most games that will run acceptably on this PC only require 640KB or less of conventional memory. Unfortunately the 5170 only came with 512KB of memory stock so although that is enough to play a number of games you really want to get a full 640KB to get the best experience with the AT.

For memory expansion I installed an Intel Above Board which has a total capacity of 2MB but also allows you to backfill the conventional memory to the full 640KB bringing the total memory of the 5170 to 640KB of conventional memory and the difference allocated to being XMS or EMS memory though usually XMS is favored for 286 class PCs. Larger memory cards are available and you can even install multiple cards up to 16MB but I’ve found little use for more then 2MB in a PC of this vintage and class.

Audio

Sound cards weren’t really a thing until 1987 and most games that will run on the 5170 well won’t necessarily require anything beyond PC speaker though a sound card does expand your options. Since I decided to go more period correct with this PC I decided an original Adlib was the best choice.

The original Ablib as seen above from 1987 uses a 1/4 inch audio jack and a simple volume knob. This card uses off the shelf parts but its YM3812 FM chip is widely supported in games. These cards are quite the collectors item these days so I can’t recommend tracking one down unless you want a strict period correct machine from the later 1980’s and have large sums of cash to burn. Almost all later sound cards like the Sound Blaster 16 have perfect Adlib compatibility so I would suggest more people go down that route. There are also a number of Adlib reproductions available for a much cheaper price if you want to keep that original Adlib look. Later Adlib cards from 1990 also switched to a more commonly used 3.5mm audio jack.

Video

In the late 80’s most 5170’s would likely have been fitted with an MDA or CGA video card though the more expensive and fancier option was the official IBM EGA card allowing 16 colors on screen at once.

There are later smaller and cheaper EGA cards with all the memory built in but the official IBM card just felt right for this PC. The IBM EGA video card only comes with 64K of video memory on the card severely limiting resolutions and colors on screen and causing some games to display an incorrect image. There is a memory expansion daughterboard as seen above which brings the card up to a full 256K of video ram. These daughterboards used to be quite rare though I believe there are third party replacements available. I unfortunately only have a CGA monitor on hand but thankfully the card can be made to display to a CGA color monitor via switches on the card and will display EGA graphics but at a lower resolution.

You can add an ISA VGA video card which would be significantly cheaper and allow the use of much more common VGA monitors if so desired though I find this much less interesting.

Overall the IBM 5170 is a capable PC for the 80’s although I do feel its CPU is a bit on the weak side even at 8MHz speeds. It’s to fast for very early PC games that require an 8088 CPU but for more demanding games of the 80’s a 12MHz or 16MHz 286 or a 386 would serve you much better. I went with a very IBM, period correct build for this article but nothing is stopping you from adding a decent VGA card and Sound Blaster 16 giving a significant boost to this PCs power and expanding the playable game library, though as I mentioned the CPU will still be a bottleneck for more demanding VGA games. In my opinion one is better off with a clone system which are usually smaller, lighter and have more things built in such as more memory and I/O ports. You also most likely do not have to worry about the tiresome setup programs required on the 5170 when using an IBM compatible which is a plus. If you are an IBM fan though this PC can be a lot of fun. The design is seen as beautiful by many IBM enthusiasts the AT is more expandable and versatile then the IBM PC and XT and the case itself is built like a tank.

Today we will be taking a look at a pretty solid 286 PC from the late 1980s. The VTI Turbo 55 although not noticeable at first is actually a Samsung branded PC which becomes obvious if we take a look at the sticker on the back or at the motherboard itself. First though let’s take a look at the front of the case.

On the front we have a keyhole for locking the computer along with two LEDs for power and HDD activity. Below this is what looks like a third LED at first but its actually a slightly recessed reset button. It’s a double-edged sword though as the recessed button does make it almost impossible to accidentally reset the PC it also makes it a potential pain if you do want to use the button to reset as you’ll need a pen or otherwise small object to use to press the button. There is no power button on the Turbo 55 so turning the power on and off is performed via a switch on the power supply.

To the right of these LEDs and reset we have two 5 1/4 drive bays. Mine are occupied with a 1.2MB 5 1/2 floppy drive as well as a 1.44MB 3 1/2 floppy drive. As I have the original box with the original specs printed on it seems this PC came stock with only the 1.2MB 5 1/4 drive. The 1.44MB drive was a later addition from the previous owner. Two bays do not leave much room for expansion but for a 286 class PC you’re perfectly fine with a pair of floppy drives. If you really wanted to you could always track down a dual floppy drive and use the second bay for a CD-ROM drive or something along those lines.

The Turbo 55 is one of those PC’s that have the keyboard connector in the front which I’m not the biggest fan of though this is a largely personal preference

The keyboard itself is pretty well made and feels like a model M with nice clicky keys. There is also an XT-AT switch on the underside in case you wanted to use it with an even older PC in your collection.

flipping the case around let’s take a look at the back.

You may notice the power supply looks well…incorrect. You would be right to think that and we will address that in a moment but first we will take a look at the built-in I/O ports. From left to right we have dual serial ports followed by a parallel port. Not a lot but as far as 286 PCs go it’s really nice to have anything built-in. Next to the parallel port we also have a curious switch with M below and C marked above. According to the documentation I could find on this model this is a monitor select switch with the M standing for mono and the C for color. The switch made no change as far as I could tell but I was using a later VGA card when I tested it so maybe it only works with CGA cards. To the right of this we have eight expansion slots with one being currently occupied by the EGA card.

Before opening the case and taking a look at the inside we can quickly talk about the power supply. The original power supply was a Han One HN-200c which when I received this computer was unfortunately completely dead.

In my foolishness though I ended up throwing it away since I just assumed it was a run of the mill AT power supply. In actuality the dimensions are a bit non-standard. The power supply I have installed currently is a newer ATX supply with an AT adaptor. It doesn’t fit quite fill the entire space so I just used some foam to fill the gap. Due to the lack of a power button I had to make sure the replacement PSU had a physical on/off switch.

The power connector on the motherboard itself is AT and any AT power supply (or adaptor) will connect to it just fine though the original HN-200C power supply did not have a split AT connector like most standard ones do.

With that out of the way lets take a look inside this PC.

Before we take a look at the motherboard lets take a look at the two expansion cards that were installed when I originally acquired this PC. If you look at the image above you’ll notice the hard drive is mounted in a vertical orientation to the right of the floppy drives.

The hard drive is run off the 8-bit controller card above and is the uncommon XT-IDE or XTA interface. This is a seldom used interface only supported by a hand full of hard drives. The Commodore Colt I reviewed some time ago also used this interface for its hard drive. The hard drive attached is a Microscribe XTA hard drive of 40MB size. I do believe this controller card and hard drive are original to this PC. Unfortunately after several hours I could not get the VTI Turbo 55 to work with any 16-bit IDE controller or SCSI hard drive controller despite the PC having 16-bit ISA slots. Fortunately for me though the stock XTA controller and the hard drive still are functional.

The only other expansion card installed was the video card.

The video card was an ATI EGA Wonder 800. I couldn’t find much information on this card but ATI was known to make some of the better cards of the time. The EGA 800 is also known to support extended EGA text and graphics modes as well as 16 color VGA modes. For convenience and due to my lack of a proper EGA monitor I replaced the card in my Turbo 55 with a slightly later 16-bit ATI VGA card.

Now let’s take a look at the motherboard itself.

The motherboard seems to be a Samsung AT 286-12 AKA SD 550 with eight ISA slots, two 8-bit and six 16-bit.

1 ) CPU – The CPU is an AMD branded 286-12 running at 12MHz. Interestingly this 286 is the N80L286-12 which is the lower powered variant running at 2.89W as opposed to 3.15 or 3.3W. the 286-12 was along with the 286-16 the quintessential and most common 286 CPU’s. Although fast enough to trigger issues with the more sensitive games meant for a slower 8088 when paired with decent VGA video card the 286-12 should have enough muscle to adequately run some slower paced VGA titles, specify point and click adventure titles.

2 ) FPU – As in most cases, my Turbo 55 came with an empty FPU socket and is a completely optional addition. For my Turbo 55 I chose to add a 287XL FPU. Unlike adding a standard 287-12 which would run at half the speed of the installed 286 (6MHz) the 287XL is actually a modified 387 FPU and should run at the full speed of the CPU which in this case is 12MHz. As I always feel obligated to mention the 287 regardless of its running speed will probably find very little use in this PC as very few games of the era took any advantage of a math co-processor chip. I did however find a CAD program installed on the hard drive which would be an application of the era that would have benefited from this upgrade.

3 ) RAM – My Turbo 55 came with a full 1MB of memory on the motherboard though from what I can see on the box 640KB and 512KB options were available. 1MB would be more then enough for a 286 class PC such as the Turbo 55 and more RAM could always be added via ISA memory cards such as the Intel Above Board if so desired.

Half of the RAM chips on the motherboard are directly soldered on while the other half are socketed.

4) Floppy connector – The floppy controller is built-in and supports up to 1.2MB and 1.44 high density floppy drives.

5) Power connector – standard AT power connector.

The serial and parallel ports can be disabled via the jumpers 11 through 14 located above the RAM while wait states can be set from 1 to 0 via jumper 21 located under the 5 1/4 bays. When I set my wait states to 0 I noticed a significant speed increase but unfortunately this created many stability issues making the machine virtually unusable.

The VTI Turbo 55 is a capable 286. It can be argued that the 286 is a fairly useless CPU for modern retro PC enthusiasts as they are to fast for earlier games while for later titles a 386 can run everything a 286 can but vastly better. I personally still find a certain charm in running a 286 system and the Turbo 55 does in my opinion make a fine 286. The 12MHz speed gives you some wiggle room for playing games and with the right video card even lets you play some slower paced VGA titles just fine. 1MB of RAM is just about perfect for the time and considering the CPU you’ll likely not feel the need to play any games requiring more than the on board 1MB of memory. If you do there is always the option to add more memory via an expansion card.

Most of my negatives of the Turbo 55 are fairly minor such as the frontal keyboard connector or the unnecessarily, at least in my opinion, recessed reset button. The biggest issue I had with the Turbo 55 was the difficulty in adding a different type of hard drive controller. XTA is a very limiting hard drive interface considering it only works with a handful of now 25+ year old hard drives of limited capacity. I tried multiple 16-bit ISA IDE controllers and drives as well as multiple SCSI controllers and drives and found none to work. This does seem to be an issue common to some 286 class motherboards and unfortunately this seems to be one of them. I did not test a modern XT-IDE controller but hopefully maybe one of these would work as a hard drive replacement.

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Some time ago we took a look at another Commodore branded PC, the Commodore Colt. Today we will be looking at its more powerful brother, the Commodore Select Edition 286 also sometimes known as the PC40-III.

As you can see from the image above my Select Edition 286 is in pretty terrible condition and is covered by a residue that seems to be from some kind of adhesive tape that was once all over this PC. On the front we can see that things are pretty basic with two small power and HDD activity LEDs as well as the Commodore badging. I have seen several variations of the case with the “Commodore Select Edition 286” badging online though, so the look of your PC may vary from this one. There are only two 5 1/2 bays both being occupied by floppy drives. The top drive is a 1.2MB 5 1/4 floppy drive while the bottom is a very mangled and non-functioning 1.44MB 3 1/2 floppy drive.

When I picked this machine up it also came with an official Commodore branded keyboard which although a bit dirty is in much better shape then the PC itself.

Like other Commodore PC compatibles of the era the keyboard port is located on the side of the PC next to the reset button. This can be annoying when opening the case as the reset button does get in the way when removing the cover so you have to take care to press the button down and then slide the case cover over it and off.

The back of the Select Edition 286 is fairly bare as well. The power button is located above the power jack. To the right of these we have a label which interestingly marks the model as a PC30-III. Starting on the far lower left we have what looks to be a serial port for a mouse though my suspicions are that like the Commodore Colt this port is actually for an Amiga style mouse. As I could not get this particular machine to get past POST I was not able to test this. Next to this we have a single RCA jack labeled “Audio”. On the Commodore Colt this port was a composite video out port. I would assume on the Select Edition 286 this port has been rewired to output the speaker sound via an RCA output but again, I was unable to test. The area next to the RCA jack has been patched closed. On earlier machines this is where the video out and switches for video mode selection would have been. Next we have a serial port followed by a parallel port. Finally we have four expansion ports, one of which is currently taken up by a video card.

Here we have the Select Edition with the top case cover removed. We can see to the right of the floppy drives a mounted hard drive and on the motherboard we can see our four expansion slots, one 8-bit and three 16-bit ISA.

The installed hard drive is a Western Digital although I never pulled it to check the model number. It’s likely a 30-40MB hard drive give or take.

Here we have the motherboard exposed with all the bays out of the way. The yellow sticker at the center of the board marks it as a PC30-III though the silk screening on the board itself, between the ISA slots, marks the board as a PC40-III.

1 ) CPU – As one would expect from a PC labeled as a “Select Edition 286” the CPU is a Siemens 286 running at 12MHz. The CPU itself in this machine looks very worn and I was barely able to make out the speed. 12MHz is a pretty healthy speed for a 286. While not as beefy as a 16 or even 20MHz 286 the 12MHz is speedy enough to allow one to play a large variety of EGA and even VGA games at acceptable speeds.

2 ) FPU socket – This would be where you would add a 287 math co-processor. In terms of gaming adding a 287 is mostly pointless as very few games that would run well on a 286 support it (Sim City), though it would be useful for running things like CAD.

3) RAM – The Select Edition 286 comes with a full 1MB of memory on-board, at least if your to trust the setup screen. Having any chips soldered directly to the board is usually a disadvantage to the user since it makes replacing failed chips more difficult. 1MB is a healthy amount for the time but to play some later games your probably going to want to add a few more MB via an ISA expansion card.

4 ) floppy / IDE connectors – Controllers for both IDE and the floppy are built into the motherboard. This is something that wasn’t even a given all the way into the 486 era so it’s a nice feature to have built in. This is extra nice since we only have four ISA slots to work with and not having to take one up with an I/O controller card is certainly a plus.

5 ) Dallas RTC – Unfortunately the Select Edition 286 uses a soldered Dallas RTC battery to save its CMOS settings. The battery is long dead preventing the PC from progressing past the POST screen. It is possible to desolder the battery and solder in a socket or solder into the battery and connect a coin battery.

6 ) Video switch – The video switch is leftover from the earlier machines which share the same motherboard. On the Select Edition 286 Commodore decided to ditch the built in video and go with a discrete EGA card in an expansion slot. I attempted to install a VGA card and was unable to get video though adjusting this switch may of solved the issue I did not attempt it.

7 ) Pizo speaker & Power connector – Commodore went with a cheaper pizo speaker as opposed to a cone speaker for this PC. The power connector like the Colt and probably other Commodore IBM compatibles uses the Amiga style power connector making things inconvenient if your original PSU should die.

The card that came with my PC was a 8-bit ATI EGA Wonder 800+. The 800+ is an interesting card as it is more or less a VGA Wonder card cut down to work as an EGA card. The card has 256K of video memory and supports various video modes including SVGA 800×600 in 16 colors. The card is also jumper free and switchless and is configurable via software.

Overall the Commodore Select Edition 286 is a completely usable 286 machine with decent speed and nice built in features. There are a few annoying things that make it a bit less useful then a more generic 286 board though, such as the lower ISA slot count as well as the Amiga style mouse port and power connector. Unfortunately I was unable to get my machine up in running for this article due to the Dallas RTC and the POST loop it locked me in which is a shame. Of course this can be fixed with a mod but I decided to use my time and resources elsewhere.

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Continuing with my “anatomy of” series we’re going to take another step back today and jump back one more generation from my previous “anatomy of a 386” article and take a look at the often overlooked 286 based PC and examine what I feel is pretty close to the “ultimate 286” setup.

The 286 was first introduced in 1982 and was widely used in the mid to late 1980’s and even into the early 90’s. They came in speeds ranging from 4mhz to 25mhz with 20mhz and 25mhz chips being fairly uncommon. For a CPU that existed in such a transitional time for DOS computers it really doesn’t seem to get a lot of love from retro PC enthusiasts and retro PC gamers. I do have a few ideas of why this may be the case though. The first reason I believe has to do with game compatibility and CPU speed. The 286 simply doesn’t fall into a position where many speed sensitive games demand it. For instance there are a number of very early CGA games that demand a 4.77mhz 8088 CPU to run at the intended speed and even on the slowest 286 will simply run to fast. On the other end there are a few games such as Wing Commander and Bubble Ghost that really need a mid range 386 class CPU and on a standard mid range 286 will run a little to slow. I have run into a few instances where a 286 “felt right” speed wise such as Ultima III with the EGA/MIDI patch but these instances seem few and far between. Many later games also need a 386 to run for non speed related reasons so while a 386 will pretty much play everything one may play on a 286 the reverse is not true. I’m guessing most enthusiasts think “why limit myself” and for the most part their right.

The second reason I believe the 286 is passed over is because finding hardware for a 386 is just so much easier and it will still run most games that run on a 286 plus later VGA games just fine. I wouldn’t call the 286 rare but in all my thrifting and buying old PC’s as far as x86 machines go I probably see the 286 the least. Even less then early CPU setups like the 8088 and 8086. The hardware is also a bit less user friendly then a 386 setup which could also be a contributing factor.

Now that doesn’t mean the 286 doesn’t have its place or is useless for retro PC gaming. It makes a fun project and it’s nice to sort of see the transition going on from the 8088 to more modern style boards such as with the introduction of 30 pin RAM on motherboards as well as the common ability to address more then 640KB on the board and things like 16 bit ISA slots which appeared on 286 boards. The 286 is also perfect for playing most EGA games and demanding CGA games that may chug a little on a bog standard 8088. a more powerful 286 such as the 16mhz and up with 4mb of RAM are also very capable of playing VGA titles from the late 80’s and early 90’s and you may be surprised how well it can play them especially provided there isn’t a lot of movement going on screen, point and click adventure games run well most of the time. the common 286-16 as well as the uncommon and border line rare 20mhz and 25mhz 286 CPU’s generally outperformed early 386SX CPU’s.

and now without further delay here’s my 286.

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To be perfectly honest I didn’t have to do much to this machine when I acquired it besides add some bells and whistles such as a VGA card and sound card. The case is that classic beige tower from the late 80’s with the large power switch as opposed to a button as well as extra large buttons for reset and turbo options and a nice green LED speed display. The turbo button slows the speed down to 10mhz though this is still to fast for some early speed sensitive games. The floppy drives I have installed are both high density drives and are a 1.44mb 3 1/2 floppy and a 1.2mb 5 1/4 inch floppy drive. In the case of a 286 I feel the 1.2mb drive is a little more important then in other machines since many games were released in that disk format during the 286 era. Obviously many of those games were also released on 1.44mb floppy and later CD but if your collecting and playing games from this era you’ll find that many picked up randomly “in the wild” will come on 5 1/4 disk. A CD drive is also very useful for a 286 since as stated earlier many games were rereleased on CD format thus having a CD drive makes things much more convenient. It is not though a necessity and you can certainly get by on a 286 without one. I’m using a slow and early x4 drive but later ones should work just fine.

Those eagled eyed readers may also notice the faux 3 1/2 floppy panel below the real disk drive. These weren’t uncommon back in the day. I’m not sure what the point of them was though except maybe to fool your buddies into thinking you had a slightly more impressive setup.

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Here’s the back of my 286. As you can see it’s pretty much the same as a 386 and 486 would commonly look. A generous number of slots for possible expansions and an AT keyboard port as well as a standard AT power supply.

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Here is a rather jumbled image of the machine with the cover removed and all the expansion cards installed.

A) Hard drive – I went with a 2gb 50 pin SCSI hard drive for this machine. They are a little less common then IDE drives but SCSI lets me make larger partitions, is a little faster in theory and takes a tiny bit of load off of the CPU which helps at these lower speeds.

B) SCSI controller – I went with a 16-bit ISA Adaptec controller for the SCSI. This card is a pretty simple Adaptec AHA-1540. My card lacks a floppy controller but simply sports a 50 pin internal connector and an external connector. I didn’t have any issues with this card and it detected my hard drive first try.

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Operating System – I have MS-DOS 5.0 installed on my system. 6.22 should work just fine but I wanted to use a little earlier of a OS to be a bit more era accurate and I didn’t want to go all the way back to DOS 3 or use the generally disliked DOS 4.

Here we have the motherboard with the expansion cards removed.

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M-209-1

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Motherboard – The board I’m using is an Ilon USA, Inc M-209. This is a rather late 286 motherboard so it supports quite a few features and CPU speeds earlier boards in general do not.

1) CPU – The most common of the 286 CPU’s were the mid to mid high range 12mhz and 16mhz 286s. These are the two most commonly used and all and all are not bad performers. I actually wanted a 16mhz 286 when I considered this project but as fate had it I ended up finding a great deal on my 20mhz 286 system that I couldn’t pass up. The CPU I’m currently using is made by Harris who also produced the 25mhz 286 which was the fastest 286 produced. The Harris 20mhz and 25mhz CPU’s were fairly rare and are sought after today by those that do want to forge ahead and build a high end 286. I strongly suspect my 286 board with its 20mhz Harris CPU could outperform as similarly clocked 386SX chip.

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2) FPU – Like the 386 the 286 could utilize a separate 287 math coprocessor to speed up the calculation of more complex math calculations. I was lucky that my motherboard came with a FPU rated for the same speed as my CPU at 20mhz. Like on the 386 the FPU chip isn’t really all that much help for games and besides programs like CAD very few games were programed to utilize the co-pro.

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3) RAM – RAM on many 286 boards can be interesting as there was a bit of a transition going on and it wasn’t uncommon to find several types of RAM being implemented on 286 boards. This is similar to later 486 motherboards where sometimes sockets for both 30 pin and 72 pin RAM could be found. The 286 itself could address up to 16MB or RAM but I’ve never seen a 286 motherboard supporting more then 4MB onboard. Currently I have 4MB installed via four 1MB SIPP RAM sticks.

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My motherboard supports up to 4mb onboard and can accept either DIP or SIPP RAM. DIP RAM are chips just like the ones used on 8088 boards for memory while SIPP RAM was a short lived style of RAM that used legs as seen below.

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4) Nic-cad barrel style CMOS battery and AT power connector.

5) Six 16 bit ISA slots and one 8 bit ISA slot – One of the great things about a 286 motherboard is that 16 bit ISA slots were now standard which opens up a huge variety of options for expansion. Since 16 bit ISA slots continued to be used on motherboards all the way up to the early 2000’s cards are very plentiful and relatively cheap compared to 8 bit ISA cards.

I/O – For my I/O controller I used a simple 16 bit ISA Goldstar controller card. I really like Goldstar cards as they always tend to just work for me. This card supports adding a serial and parallel port as well as two high density floppy drives and two IDE devices such as my CD-ROM drive.

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Video – For my video card I went with an ATI VGA Wonder XL24 card. The VGA wonder cards were well regarded VGA cards throughout the 80’s and very early 90’s. While not as fast overall as cards like the Tseng ET4000 they had a few features which I felt lent themselves more to a 286 class machine. The VGA Wonder XL24 card that I’m using is the last and most powerful Wonder card in the series. Released in 1992 this card is a 8/16 bit VGA card that offers 1MB max of RAM and improvements in speed and bug fixes over earlier cards in the series. The card offers one BUS mouse port which was a type of mouse connector similar but not compatible with the PS/2 standard as well as two monitor ports. The thing I really like about these cards is that they have both a 15 pin monitor port for VGA as well as a 9 pin port for TTL CGA.  The card also could auto detect the type of monitor connected rather then requiring the use of dip switches to tell the card what it’s displaying to. I find this feature very hand for a system like a 286 where you may want to be using a VGA or CGA monitor depending on what your playing. Although the VGA wonder XL24 claims to offer 100% CGA compatibility this may not be completely true. Despite this the compatibility with CGA is quite high and having the ability to use a true CGA monitor is always a great option with a 286 where your likely to be playing a lot of CGA games as well as later EGA and even VGA games. The ability to use both types of monitors and a boast of very high compatibility is definitely a plus.

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Sound – Lastly we come to sound. I chose to use the 8 bit sound blaster 2.0 card with the CMS sound compatibility chips installed. The sound blaster 2.0 is fully adlib compatible and offers superior quality compared to the earlier sound blasters. The main draw of this card though was the option to add chips for CMS compatibility or “Creative Music System”. This was a earlier standard used by Creative in their first “Game Blaster” cards and some earlier games use this. The CMS compatibility on the SB2.0 with the added chips isn’t quite 100% but it is close. At one time finding the third PAL chip needed for CMS compatibility was very hard but thankfully someone figured out how to reverse engineer the chip and made it available for most revisions of the SB 2.0 card such as the 049151 revision I am using. If you do have a card with the CMS chips installed remember to remove jumper jp9 as circled in the image below to enable them.

Add the line

SET BLASTER=A220 I7 D1 T3

to your Autoexec.bat file to initialize.

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Before I wrap this article up I just wanted to post a few images of another motherboard I have. This one being a later 286-16 board.

28616

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Notice That this board uses standard 30 pin sockets for RAM.

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My 286 when I originally acquired it complete with monochrome amber screen monitor.

So what’s my opinion of the 286 and do you need one as a retro PC gamer/enthusiast? The short answer is no. Personally I enjoy the 286 for its somewhat uniqness but I can understand why it is usually overlooked. As I stated at the beginning of the article it’s just to fast for the earliest CGA games and as for anything later it cant really do anything a 386 cant do better. Also compared to a 386 the 286 is harder to find parts for and being generally less capable. If your short on space Id say pass on building a 286 but if you have space, cash and time to spare they can be fun little machines that bridge the small gap between the somewhat archaic 8088 and the somewhat modern feeling 386.

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