IBM PC/XT 5160
Posted by muse_head@reddit | vintagecomputing | View on Reddit | 17 comments
These seem harder to find here in the UK compared to across the pond. I put together this system from various different sources!
Computer itself: FB marketplace, extremely dusty and dirty from decades of storage. Cleaned up nicely. Has 640KB RAM and 20MB HD.
Monitor: IBM 5153, a different FB marketplace find, had the cable cut off but worked fine with a new one attached.
Keyboard: eBay, bought as "not working" but worked fine.
Manuals: Also eBay.
Upgrades: eBay sourced EGA card (big improvement even with the CGA monitor), and 3.5" floppy drive.
sarajevo81@reddit
Do XTs still have that god-awful 4.77 CPU?
And IBM was very brave using THREE electrically incompatible monitors with one plug.
canthearu_ack@reddit
The XT does indeed use the 8088 running at 4.77mhz.
The three monitors are not electrically incompatible, so you normally won't fry stuff if you plug the wrong monitor in. But you won't get a stable image if you try and use a Monochrome screen on a CGA or EGA card, or the other way around.
You can use an EGA screen on both CGA and EGA graphics cards.
You can use a CGA screen on an EGA card, but you must set the dip switches on the EGA card for using a CGA screen otherwise text modes will attempt to use the high resolution 21.85 khz resolution that the CGA screen won't be able to display. If you switch the EGA card to CGA screen mode, it will use the CGA 15.75 khz resolution for text output.
LittlePooky@reddit
You really cleaned it up very nicely. It is amazing that the manual lasts this long as well. I love the good old days when any program or most hardware came with printed manuals in slip cases. This is so cool!
JasonMckin@reddit
I loved Commander Keen!!! Weirdest sounds in that game.
Wait are you sure it’s a CGA monitor? It’s displaying a lot of colors there. Is it an EGA monitor too?
The thing that’s hard to remember is being used to IBM PCs with mono or CGA monitors and low single digit mhz CPUs and then seeing computers like these at retail stores was mind blowing.
muse_head@reddit (OP)
It's a CGA monitor but an EGA graphics card, the monitor can display low resolution EGA graphics modes (like most EGA games use) but not high resolution modes.
JasonMckin@reddit
I’m confused. At 320x200, CGA can only display 4 colors while EGA can display 16.
I see 16 colors in the screenshot.
So that is an EGA monitor, right?
I’m not sure what it means for a CGA monitor to display EGA?
muse_head@reddit (OP)
A CGA card is limited to displaying 4 colours at 320x200, but a CGA monitor doesn't have such a limitation - it's just a dumb device and doesn't know what's plugged into it. The CGA and EGA modes at 320x200 both have a horizonal sync of 15.75 kHz so a CGA monitor is happy to display the EGA 320x200 at 16 colours mode. But it cannot display the high resolution EGA 640x350 mode because it requires a 21.8 kHz horizonal sync which is not compatible with this monitor.
It was quite common in the 80s for people to use a CGA monitor with an EGA graphics card, because EGA monitors were very expensive. Many people would just upgrade their graphics card but keep the same CGA monitor instead.
sarajevo81@reddit
And obviously you can have your loadable (illegible) fonts and the 512 character set.
son-of-a-door-mat@reddit
i still can hear it 35 years ago!
achbob84@reddit
It’s CGA. The EGA has light coloured knobs.
Both CGA and EGA monitors can display 16 colours, but EGA has a high resolution mode as well. EGA cards can handle those 16 colours in graphics modes, while CGA can only do 16 colours in text mode.
sjoskog@reddit
Wow, EGA looks pretty good on that old PC.
echocomplex@reddit
Wow does Keen run full speed on those specs?
muse_head@reddit (OP)
It's playable, but it runs slowly. Probably needs a 286+ ideally!
echocomplex@reddit
Wonder if keen 1 would work better
reffak@reddit
Our first home PC, green screen. Now there is a memory or 2 there. That keyboard was something else. Typing on some MS keyboard but I do miss that clackity clack of that keyboard and the solid feel.
saraseitor@reddit
Congrats! It looks beautiful. It's fantastic you found one with a working hard drive!
AngryK9_@reddit
Nice. Looks pristine.