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Shiny new XT clone!

S

shawn510

Experienced Member
Joined
May 6, 2008
Messages
95
Location
Alabama
We just moved to a new house with a little shed for me and all my "projects". So, I have started to get into all the stuff I had in storage which includes a never finished "barebone" XT clone.

I picked it up a few years ago when a local PC maker, Softek, finally gave up. They had this thing setting out on the sidewalk for anyone to get, so I scooped it up. Only I did not have room to do anything with my collection until now.

It is all pristine on the inside, with no drives or cards installed. There is a loose cardboard box with what looks to be some drive mounting hardware. I'll try to post pictures tonight. It is a Rakon mainboard, with what looks to be 256k of ram and eight slots. The case is a standard IBM lookalike type clone case. It still has the plastic covers over the drive bays, two half hight covers and one full.

My plan is to finally build to this thing out and give it the chance to actually run. I am not sure how I want to configure it, so any suggestions are welcome. Funds are tight, so this will be a slow acquisition for awhile.

I do have a WD hardcard in it's box that was given to me by a friend. It's status is unknown but it looks mint. So I plan to use that for the harddrive. I have a 5 1/4" floppy, but it is beige and a high density drive at that. No other 8 bit cards, except for a sony CDROM with 8bit card that I might still have in storage back in SC.

The ram is loose chips, is there anyone still selling those. Or, am I better off looking for an filled out ram board?

What do you guys think I should go for in filling this thing out? Thanks!
 
Pictures as promised. Shrunk the size down to make them more manageable.
 

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shawn510 said:
According to what I could find online, I need 9 more 41256 and 18 4164 chips. That gives two banks of each kind of chip.
Click to expand...

Well what I have sitting here beside me is 18 256-10 chips and 9 4264-10 chips (they are the same as the 4164s), so, let me dig up another bank of 64 x 1s and then we'll talk in PM
 
Druid6900 said:
Well what I have sitting here beside me is 18 256-10 chips and 9 4264-10 chips (they are the same as the 4164s), so, let me dig up another bank of 64 x 1s and then we'll talk in PM
Click to expand...

Thanks!

I am still unsure of which way to go on the video. I was thinking that I wanted at least EGA. It looks like EGA cards are not ahrd to find, but EGA monitors seem to be scarce. How good is the CGA/EGA compatiblity on the 8-bit VGA cards? VGA screens seem to be a dime a dozen these days. maybe I'll settle for CGA, I saw a few CGA screens on EBAY.
 
shawn510 said:
I am still unsure of which way to go on the video. I was thinking that I wanted at least EGA. It looks like EGA cards are not ahrd to find, but EGA monitors seem to be scarce. How good is the CGA/EGA compatiblity on the 8-bit VGA cards? VGA screens seem to be a dime a dozen these days. maybe I'll settle for CGA, I saw a few CGA screens on EBAY.
Click to expand...

EGA is a hard target to match, due to the monitor issue.

VGA completely emulates EGA, 100%. The monitors are also a tad easier to find ;) CGA, however, they usually don't emulate very well because the same ports in CGA do something else in VGA. Does that mean you're screwed? No, it means you need to find a pre-1992 card WITH SOFTWARE, because most cards made that time or earlier contain special code and software to "force" CGA compatibility. For example, running said program forces the font to 8x8, and port writes behave like CGA instead of VGA. But each software utility to do this is specific for the card it came with.

CGA cards are somewhat easy to find, and CGA monitors are easy to find too, except 1. CGA monitors, even if free, are expensive to ship, and 2. there's always the problem of how to repair them when they break.
 
The best solution is to get an old multiscan / multisync monitor which supports just about every classic computer display standard: MDA, Hercules, CGA, EGA, VGA, Super VGA, Commodore 128, Apple IIGS, Amiga, Atari ST/TT/Falcon, Tandy 2000, CoCo 3, etc. -- sometimes even standard composite video, like with my Mitsubishi Diamond Scan monitor. :)

Of course, you need the appropriate cable for each, but MDA, Hercules, CGA, and EGA (and C128) are easy because they all use the same: a plain male-to-male DB9 cable with all pins wired straight through.

And as for VGA emulating CGA, the two biggest problems I've encountered are lack of support for 160x100 "hacked text mode" graphics and lack of support for the "undocumented" red/white/cyan graphics palette (which VGA displays as standard magenta/white/cyan instead).
 
vwestlife said:
And as for VGA emulating CGA, the two biggest problems I've encountered are lack of support for 160x100 "hacked text mode" graphics and lack of support for the "undocumented" red/white/cyan graphics palette (which VGA displays as standard magenta/white/cyan instead).
Click to expand...

The specialized programs I refer to (that come with the cards on a "driver" diskette) are supposed to handle that. One such card/util so completely reprogrammed the card that you had to reboot the machine to get it out of that mode :) and while in the mode, CGA compatibility was 100% including the third palette.
 
The NEC MultiSync 2A or 3D is a good choice if you can find a working one.
I found a working 2A awhile back, I've used it in VGA mode
but have not made/purchased an adapter to use it with CGA/EGA.

I also have a Mitsubishi AUM-1381? with many connectors on the
back. I think this monitor handles about anything but I've only used
it for VGA as I don't have any other cables for it.

I don't think either of these monitors are easy to find. The NEC's
I'm sure were much more common but unfortunately I think most have
been trashed by now.

vwestlife said:
The best solution is to get an old multiscan / multisync monitor which supports just about every classic computer display standard: MDA, Hercules, CGA, EGA, VGA, Super VGA, Commodore 128, Apple IIGS, Amiga, Atari ST/TT/Falcon, Tandy 2000, CoCo 3, etc. -- sometimes even standard composite video, like with my Mitsubishi Diamond Scan monitor. :)

Of course, you need the appropriate cable for each, but MDA, Hercules, CGA, and EGA (and C128) are easy because they all use the same: a plain male-to-male DB9 cable with all pins wired straight through.
Click to expand...
 
mikey99 said:
I also have a Mitsubishi AUM-1381? with many connectors on the back. I think this monitor handles about anything but I've only used it for VGA as I don't have any other cables for it.
Click to expand...
That's exactly the one I have. For digital RGB (MDA/CGA/EGA) all you need is a plain DB9 cable. For analog RGB (Amiga, Atari ST, VGA) it has a 25-pin port on the back and I was lucky to get the appropriate HD15 to DB25 cable for it for VGA.

Sony also made some monitors which will display anything from CGA up to Super VGA. These are highly prized because of the high quality (0.25 mm dot pitch) Trinitron picture tube.
 
I discovered something interesting while googling. Apparantly EGA was used in many arcade machines along with CGA and VGA. So you can buy new arcade monitors that suport EGA or all three with a switch to go from TTL to analog.

They are not at all cheap, however. And they come as a bare unit without any sort of case as they are meant to go inside arcade units.

Still it may be an option for those with enough cash who want to replace a dead EGA or CGA monitor; you could get one to fit the existing case then wire it up into the old shell.

I however don't have enough cash. But I'm no hurry either, this will be a many month project. Slow burn is my new mantra.

Check this out: http://www.happcontrols.com/monitors/49305600.htm

Edit to the edit: Here is one stright from wells-gardner that looks to be a full-on multisync for under 200 http://www.wellsgardner.com/products/details.asp?iCat=2&iSubCat=10
For a new monitor that's not too bad. And it looks like it would handle just about anything a vintage pc could throw at it. Even includes the CGA adapter cable.
 
Last edited:
nice machine you have there. looks like it's missing a lot of RAM! it looks exactly the same as my BMI clone.
 
vwestlife said:
That's exactly the one I have. For digital RGB (MDA/CGA/EGA) all you need is a plain DB9 cable. For analog RGB (Amiga, Atari ST, VGA) it has a 25-pin port on the back and I was lucky to get the appropriate HD15 to DB25 cable for it for VGA.

Sony also made some monitors which will display anything from CGA up to Super VGA. These are highly prized because of the high quality (0.25 mm dot pitch) Trinitron picture tube.
Click to expand...

Thanks for the tip on the DB9 cable. Picked one up from eBay for
six bucks shipped. Of course after wasting an hour or more digging
through all my boxes of cables cause I was sure I had one somewhere :)

Tested the cable last night and it works great. I already had the 25 pin
cable, it came with the monitor.

BTW, heres a link with some info and the pinouts of the AUM-1381

http://xrootd.slac.stanford.edu/~gowdy/Amiga/A4000HardwareV1_Sections/monitors.html
 
mikey99 said:
Thanks for the tip on the DB9 cable. Picked one up from eBay for
six bucks shipped. Of course after wasting an hour or more digging
through all my boxes of cables cause I was sure I had one somewhere :)

Tested the cable last night and it works great. I already had the 25 pin
cable, it came with the monitor.

BTW, heres a link with some info and the pinouts of the AUM-1381
Click to expand...

I'm in the same boat.

I got a Taxan MDA/CGA/EGA monitor from Micom2000 and I KNOW I have a full pinset DB-9M to DB-9M cable around here somewhere, I've seen it.

I found one that would work for a mono monitor, but, it's a few pins short for CGA/EGA, so, I keep looking until I give up, buy one and then find it.
 
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