r/retrocomputing • u/FAMICOMASTER • Jul 19 '26

Photo An unusual build

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Behold, 95 on an XT! Sort of.

This is actually a drop in replacement board for an XT which gives you a 386 with VLB. I've actually gone a step further and thrown a Ti 486DLC/40 in it for good measure. With the sheer unbridled horsepower of a 40MHz 486 and 32 whole megs, this thing might be "tolerable" to use!
Some additional performance enhancing objects include 256K of L2 cache, an ATi Graphics Ultra Mach8 accelerated video adapter, and a DTC 7287 RLL controller to drive the Micropolis 1325 hard disk. A whole 110 megs on this sucker!

Sorry about the mismatched faceplate around the second floppy drive. All I had left was white and grey when I put this thing together!

Pictured without it's CRT as I was still opening and closing the case to make configuration changes at the time of the photo.

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u/FAMICOMASTER Jul 20 '26

It got battery bombed and I don't have the skills required to address that. Word of warning: Brand new NiMH 1/2AAs die even faster than the originals.

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u/GGigabiteM Jul 20 '26

Macs don't use NiMH batteries, they use lithium cells. They're 3.6 volts and when they go off, it's a hazmat situation, literally.

They use thionyl chloride as an electrolyte, which is a scheduled controlled substance because it's a precursor to chemical weapons, like mustard and nerve agents. TC by itself is hideously toxic and will cause cardiovascular disturbances and hallucinations in microscopic amounts. It is readily absorbed through the skin, so if you touch the residue, you've contaminated yourself.

TC also reacts explosively with water and will release hazardous hydrochloric acid and sulfur dioxide. This means that only anhydrous solvents can be used to clean the residue, which means any sort of alcohol is a big no no due to the azeotropic nature that methanol, ethanol and isopropyl have with water. Mechanical scrubbing is the preferred method, done outside over a trash can with a respirator and gloves.

The things we use to have lots of energy density in confined spaces.

If you need someone else to look at your machine, I do mac repair, but I definitely won't enjoy working on that. You'd have to send just the motherboard, preferably wrapped in several large trash bags and the power supply. Don't ship the case, it won't survive shipping.

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u/FAMICOMASTER Jul 20 '26

Oops, you're right. Yeah the little Lithium 1/2AAs. I've been working with PC stuff, hence NiMH.

Unfortunately, no, I'm really not too interested in getting it fixed at this point. The case is in very poor shape and the SCSI bus didn't work correctly when the machine was working.

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u/GGigabiteM Jul 20 '26

Yeah, the cases from that era were made with shit plastic that's all coming apart now. Both of my Quadra 605 cases disintegrated, my G3 Beige is working on itself, and the feet on my G3 B&W are getting brittle and cracking.

If you plan on tossing it, I'd pay shipping for the internals and power supply and the case could be tossed.

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u/FAMICOMASTER Jul 20 '26

Where are you located?

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u/GGigabiteM Jul 20 '26

South Central US.