Another Vintage PC

[CelGen]

Before I foul up this subforum with a non-mac conquest I'll put some detail into this.

(Last thread like this, I promise!)

At about the time Apple released it's biggest mac ever, the Quadra 9x0, IBM went and built the largest and last purebred Microchannel machine. The PS/2 Model 95 is a beast. Like the quadra, these machines are also amazingly upgradeable.

It sports eight 32-bit MCA slots, space for an additional floppy, five 5.25" SCSI devices, eight 72 pin DRAM slots (with varying levels for support of parity an ECC ram, as well as the ability to handle up to 128mb of ram) and a brilliant CPU complex that came in five different varieties ranging from the 25mhz 486SX to the Pentium 66.

Now generally because these systems are the best thing you can get your hands on they usually don't sell for cheap but after MANY unsuccessful attempts at securing one I FINALLY nailed a system for $200 shipped. Unfortunately it arrived damaged so I ended up taking two weeks to carefully reassemble the plastics and potting them with epoxy. Thankfully Paypal gave me a full refund as an early christmas present.

Anyways, today I finished repairing it and FINALLY had the chance to start upgrading it.

CPU Complex: Type 3

CPU: AMD Am5x86-P75 (OC'd to 150mhz)*

Ram: 64mb ECC DRAM (installed in pairs of 16mb)**

Hard Drive: IBM 0663-H12 1gb drive

Optical: IBM CD-ROM II***

Video (2D): XGA-II

Video (3D): Silicon Graphics IrisVision

Sound: Crystal Sound

Network: IBM EtherStreamer/32

SCSI: Standard "Spock" controller with 2mb of cache (!!!)

Floppy: IBM 2.88mb diskette drive

*Not used ATM due to missing components

**On Order

***Not installed yet due to missing bezel

There's also lots of peripherals attached. I have an extra parallel port and two serial ports to handle a Calcomp drafting tablet, modem and ZIP drive. The system will be bundled with a Model M and a "Dovebar" mouse. Due to missing drivers for the IrisVision under OS/2 I'll be running a mix of PC-DOS and Windows for Workgroups 3.11. It will run Doom with no issues and with tweaking will be useable for Quake.

Unfortunately the full potential of the IrisVision is limited to applications like 3D Studio and AutoCAD Release 12 which supply their own drivers for the card. By the way, the reason I'm using a 1gb drive is because this machine uses an IML partition to hold an enhanced BIOS and a bit of extra microcode for the POST. BEcause of limitations brought on by it I cannot use a system disk larger than 1gb.

The only thing I'm actually having trouble sourcing is IBM's matching 20" monitor. I already have the lsightly newer P201 but the monitor I'm after has IBM's more traditional PS/2 style bezel and BNC jacks on the back.

(I am open to trading monitors if you want my P201 with it's 13W3 connector. )

 

[Byrd]

That's a cracking PC, was it just a multiplier increase to overclock the 5x86? In addition, surely you can run more than 1GB drives on such a beast? It could do with a 20 or 40GB unit

 

[uniserver]

Thankfully Paypal gave me a full refund as an early christmas present.

sorry what?

So … lol and the seller got stuck with paying the shipping too?

 

[luckybob]

If I knew where kamloops, canada was, i'd come over and steal that beast from you. Honestly, the PS/2 IBM series had MANY flaws, but good looks was NOT one of them.

 

[CelGen]

That's a cracking PC, was it just a multiplier increase to overclock the 5x86? In addition, surely you can run more than 1GB drives on such a beast?

The problem is that because the Type 3 complex has a 50mhz FSB it is super fast but it's really hard to upgrade. The Kingston Turbochip (the Am5x86 came in a number of packages) has its multiplier set at x4. the push from 133mhz native to 200mhz is simply too much for the chip and it won't POST. You can however FORCE the chip to x3 which makes it run at a stable 150mhz by removing pin R17. I added a jumper so I can keep the pin but switch between x3 and x4 whenever.

While this should work, IBM likes to make up its own rules every so often. When the speed of the 5x86 changes, so does the CPUID. IBM's microcode doesn't like that and thus it won't POST. You're forced to use an Interposer to run the machine at 150mhz.

If I want to add another hard drive I can add a 4gig barracuda down the line, keeping in mind that the 1gb drive is mandatory. I still got plenty of space for expansion. I'd kill for the fill height 5.25" bezel though so I could fit a Magneto optical drive in but I don't believe they exist.

So … lol and the seller got stuck with paying the shipping too?

The shipping was split between him and Pitney Bowes. I did something right early on and noted with the courier when it arrived that I could feel the contents of the box shifting around. That note went into the claim, proving that the item was either originally packaged poorly or repackaged poorly by Pitney Bowes.