Retro P24T/5x86/486 ISA/VLB Rig

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Retro P24T/5x86/486 ISA/VLB Rig

Postby FrostyTheSnowman » 2019-7-26 @ 07:21

Retro P24T/5x86/486 ISA/VLB Rig

I have been on an ISA-compatible kick for a while now with some of my other builds (see signature) in order to maintain full DOS sound support, and somewhere along the way I decided that I should build a full ISA/VLB 486 system for my retro collection too. :cool:


Motherboard: MV35F ISA/VLB AT w/OPTi chipset, 30/72-pin SIMM support, 128MB RAM support, 512k Cache support and P24T support (was new-old-stock per the seller - it certainly looks like it too!)
L2 Cache: 256k (upgradable to 512k)
CPU 1: Intel Pentium Overdrive (P24T) @ 83Mhz (overclockable to 100Mhz stable)
CPU 2: Evergreen 586/AMD 5x86-133 @ 133Mhz
CPU 3: Intel 486 DX2/66 @ 66Mhz
Hard Drive: Seagate PATA 40GB (not even close to period correct :lol: )
Disc Drive: Sony PATA CD-RW (also not even close to period correct :lol: )
Floppy Drive A: Mitsumi 3.5"
Floppy Drive B: TEAC 5.25"
I/O Board: DTC 2280 Super I/O ISA
Video: Cirrus Logic GD5429 VLB 1MB (upgradeable to 2MB)
Audio: Yamaha OPL3-SAx ISA (YMF719E-S w/6.8nf Low-Pass Filter mod and Reversed-Wavetable fix) w/PC Speaker Passthrough Cable
Modem: Wisecom WS-3314JS3 56K ISA (somewhat period correct)
PSU: Unknown brand, AT, has AC passthrough port for monitor, seems solid - no leaking caps but needed to replace 80mm fan (was making a lot of noise on startup)
Case: Unknown brand, AT, has a 3-digit LCD screen with turbo button support (LCD screen's output changes in to 'SLO' when turbo is off)


Monitor: HITACHI SuperScan Elite 611 (CM611U-511) 17" VGA Monitor w/.22mm Dot Pitch, 15Hz support, Sync-on-Green support and Geometry/Convergence menus
Speakers: Advent Desktop Speakers (w/low-level 3.5mm subwoofer output)
Keyboard: Keytronic AT Keyboard
Mouse: Logitech TrackMan (3-button) Serial
Gamepad: Gravis Gamepad (4-button)

Pending upgrades (in order of priority):

3Com 3C509B-C Etherlink III ISA (should be arriving soon)
512k L2 Cache (should be arriving soon)
Additional 1MB RAM for GD5429 for a total of 2MB (need to research the correct chip, once known it will be ordered)
VLB-based Super I/O card (would be nice to have)
Additional 64MB RAM for a total of 128MB RAM (completely pointless, but would also be nice to have)

NOTE: Part 1 ZIP file contains pictures of the computer and it's peripherals, Part 2 ZIP file contains pictures of the monitor's image quality/features.
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Re: Retro P24T/5x86/486 ISA/VLB Rig

Postby FrostyTheSnowman » 2019-8-04 @ 01:19


1. I found a damaged GD5430 PCI video card locally - it has a NASTY scratch through the back (you can almost see it through the PCI connector) and was unusable (not worth going through the trace repair process either) so I got it for free as a donor card for RAM. Unfortunately it did not have removable RAM (sockets were unpopulated) so I used my hot air gun to safely remove the soldered-down RAM modules from the GD5430 PCI, then I cleaned/prepped the pins and installed them in my GD5429 VLB (total of 2MB RAM now, performance is improved via interpolation feature on GD5428/5429/5430+ when 2MB is installed).

2. Installed a Promise VLB Super I/O card (PDC20630) for improved IDE speeds/etc... provides both VL/IDE and ISA/IDE connectors. :)

3. Installed a 3Com 3C509B ISA network card.

4. Installed a Wisecom WS-3314JS3 ISA 56K modem.

Still waiting on my 512K cache to arrive in the mail... should be here soon! :cool:
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