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IBM PC and PC/XT in a Newer Case

G

Great Hierophant

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One of the things I dislike about my IBM PC/XT is its huge, heavy and cramped case. I would much prefer putting it into a lightweight case, but I am concerned about form factors, mounting holes, power supplies, and 5.25 inch bays.

Form Factor & Mounting Holes - AT cases tend not to be lightweight, they tend to be made of the same kind of sheet metal as IBM's cases. Would a 5150/5160 motherboard work in an ATX case? Would their be appropriately spaced holes to mount such a board?

Power Supply - The 5150 and 5160 each have their own power supply. I have heard of ATX to AT adapter plugs. Apparently, the only difference between an XT and an AT power connector is an additional +5V line with the AT connector, which is left unconnected on the XT board. However, the XT and AT machines use a switch on the power supply to turn the system on. How would an ATX power supply receive a signal to "turn on" from a motherboard without that capability?

5.25 Inch Bays - The half-height IBM diskette and fixed disk drives inside my later model XT are large and heavy. Would a lightweight case possess the structual integrity to hold these drives in place or would the rails warp and cause the drives to fall?
 
Great Hierophant said:
One of the things I dislike about my IBM PC/XT is its huge, heavy and cramped case. I would much prefer putting it into a lightweight case, but I am concerned about form factors, mounting holes, power supplies, and 5.25 inch bays.
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Cool idea, I've never tried it myself but have heard of people who have, not sure if things are going to line up all Happy, one way to find out =)


Form Factor & Mounting Holes - AT cases tend not to be lightweight, they tend to be made of the same kind of sheet metal as IBM's cases. Would a 5150/5160 motherboard work in an ATX case? Would their be appropriately spaced holes to mount such a board?
Click to expand...




Power Supply - The 5150 and 5160 each have their own power supply. I have heard of ATX to AT adapter plugs. Apparently, the only difference between an XT and an AT power connector is an additional +5V line with the AT connector, which is left unconnected on the XT board. However, the XT and AT machines use a switch on the power supply to turn the system on. How would an ATX power supply receive a signal to "turn on" from a motherboard without that capability?
Click to expand...

Depending on the type of chassis you choose depends on the type of Power supply you use. An AT chassis will go with an AT power supply and same for the ATX parts. It all has to do with the switch. ATX uses a momentary depressor and AT (for the most part) uses a double throw rocker switch. Its easiest to use the power supply that the chassis is meant for.

ALSO on top of that, choosing an ATX setup will require getting a kit, it converts the motherboard connection and adds a switch that connects to the power supply instead of the motherboard.

I recently gutted my original 63.5 watt PSU from my 5150 and replaced its guts with those of a 250watt AT PSU, works great and now my SCSI hard drive will spin up ;) At is just the easier way to go for you I think.


5.25 Inch Bays - The half-height IBM diskette and fixed disk drives inside my later model XT are large and heavy. Would a lightweight case possess the structual integrity to hold these drives in place or would the rails warp and cause the drives to fall?
Click to expand...

Oh come on, they arent THAT heavy, and half-heights at that. Even the full heights arent THAT heavy... I weigh close to 300 lbs and my rather large self can stand on most of my computer cases without risk of implosion, even the cheap aluminium ones.
 
Yes, it should be possible to use an ATX case, but it depends on who manufacturers it. I found that my XT motherboard would not fit in all of my AT and ATX cases because some of the screwholes don't line up properly....so you might want to check that out, or you may not have any places to secure your board. I recently put one of my old baby ATs into an ATX casing with ATX power supply. I am pretty happy with the results. I am using an Inwin Desktop ATX case with metal standoffs. Try to get the metal standoffs rather than the crappy plastic ones.

Concerning the switch, on the AT --> ATX converter I am using, an additional push button mechanical switch is supplied that replaces the one that comes with the ATX case. It looks like the replacement switch is coming directly off two of the ATX lines, and there is no additional circuitry required. So, if your adapter doesn't have one (it should), it should be easy to make a modification.

Oh, and I have one recommendation about changing the switch. ATX cases usually have a spring under the plastic power button. When you replace it with an AT switch, you will need to remove the spring or the button won't function correctly. Just trust me on this one, it drove me crazy for several days before I figured it out.
 
Trixter said:
Blasphemy! The reason I love my XT is *because* of it's huge and heavy case. Nothing says IBM like a personal computer that can be used to bludgeon your enemies into submission.
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Hehe totally agree. Fakers have to be put to the 'throw down the stairs test'.
 
One thing I noticed when I got my AT was that it was even bigger, heavier and better built than my XT. I didn't think that was possible! :lol:

I don't think I have ever seen a computer better built than an early IBM PC, XT or AT.
 
I suppose the fact they are well built was one way to express that IBM took personal computing seriously once they entered the market. Anything half-hearted, fragile, cheap looking was out of the picture if I understand correctly.

(Now, if it can be said that either of the Apples, TRS, Commodore PETs and so on either are fragile or cheap looking.)
 
Jorg said:
Hehe totally agree. Fakers have to be put to the 'throw down the stairs test'.
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Ah yes, the famous "throw down the stairs" test. Yesterday, I was carrying an old floppy drive to the basement for testing. When I reached for the light switch, it slipped out of my hands and fell down the stairs bouncing all the way.

It found to be not worthy. :-(

After I finished crying, I packaged the old and very damaged drive into a small box for component stripping and proper burial of the deceased.

It was one of those "I wish I hadn't of done that" moments.

:)

Andrew Lynch
 
Trixter said:
Blasphemy! The reason I love my XT is *because* of it's huge and heavy case. Nothing says IBM like a personal computer that can be used to bludgeon your enemies into submission.
Click to expand...

Forget the computer, you could bludgeon someone to death with the XT keyboard alone!
 
I'm the complete opposite of the original post......THIS is my Pentium III....big, heavy, mean, and has been upside down, on it's side, all from being dropped, and even with the modded and bolted together chassis, it's STILL standing with no problems to this day.
gemsummer07.jpg


And even heavier and meaner to carry is the 26" X 14" X 5.25" 286 GEM. This sucker has flown down a flight of stairs, and only has a scratch or two to show for it, and no bad sectors. And it apparently came factory equipped with 1mm thick textured paint.

2861.jpg


And I'm the same way about keyboards too, my top three faves are the Northgate Omnikey, IBM Model "F", and the IBM Model "M" in that order. All three could double as battle arms, though the Northgate less so than the IBMs.
 
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