2 layers231.1 × 106.7 mm
4 layers240.5 × 69.4 mm
Virge vlb
computerguy096/Prometheus-VLB4Open-source VESA Local Bus video card
- Size
- 240.5 × 69.4 mm
- Copper layers
- 4
- Thickness
- 1.61 mm
- Parts
- 75
- Nets
- 337
- Pads
- 909
- Tracks, vias
- 2,205, 454
- Pours
- 25
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 23 Mar 2026
- Updated
- 4 Nov 2026
Overview
Virge vlb is an open-source printed circuit board by computerguy096, from the computerguy096/Prometheus-VLB repository on GitHub, published under the GPL-3.0 licence. It is a 4-layer board of 240.5 × 69.4 mm with 75 parts on 337 nets, routed with 2,205 tracks and 454 vias.
It is built around the 74LS245SC. Its parts include 30 capacitors, 27 resistors, 9 ICs, 2 connectors and 1 crystal.
Main components
1README
README.mdPrometheus VLB - an affordable way to get a fast video card for your VLB systems
This is an open source video card, designed to be used in systems with a VLB slot, like a 486 class machine. It's designed around the S3 Trio64V+ video chip (86C765), which can be found in many PCI video cards, as wel as separately. As a bonus, this particular chip allows for a very easy implementation for the VL bus, with almost no support components required, even the RAMDAC is built into the chip. The card was designed from scratch, using only the official datasheet and photos of an STB Powergraph 64 for a few visual references.
Features
- S3 Trio64V+ (86C765) or S3 ViRGE (86C325)1 video chip, with a powerful and very compatible 2D core, perfect for most DOS games
- up to 2MB of fast page or EDO memory, with clearance for SOJ sockets
- configurable address range, with 32MB, 64MB and 1024MB as options
- simple design, built in RAMDAC, only requires a few extra parts
- fully configurable registers with pull-downs, allowing the tuning of various parameters like memory timings, etc.
- flexible EEPROM implementation, allows DIP28, DIP32, as well as PLCC32 footprints
- common VGA connector placement, allows reusability for many of the old metallic brackets
- small PCB, which does not extend below the card edge in the front, so it will not collide with keyboard controller chips on some boards
Documentation
Trio64V+ datasheet can be read here, and the ViRGE datasheet here.
FAQ
Q: Is this for sale? Where can I buy one?
Nope, it's not for sale, and I do not have any intentions to sell them. However, I am an advocate for open source hardware so the design is fully public (the gerbers, the schematic, everything, all provided under GPLv3) so you can build your own card freely.
Q: What parts do I need to build a card?
There is a CSV BOM included, as well as an interactive HTML BOM, with all the parts and their quantities listed. The main thing to acquire is the S3 chip itself, which can be salvaged from PCI cards or bought as NOS trays. Be careful with the chip model, only 86C765 and 86C325 are fully pin compatible and will work!
Q: What about the video BIOS?
There is a 1 wait state BIOS from the STB Powergraph64 available right here.
You may try faster 0 wait state BIOSes, though their stability and compatibility with boards is not guaranteed.
Q: Where can i find the gerber files?
At
/kicad/gerberon this repo.
Footnotes
Footnotes
-
S3 ViRGE support is experimental in VLB mode, since there are no drivers available for it. ↩
Parts
75| Qty | Value | Footprint | References |
|---|---|---|---|
| 15 | 33R | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R5, R6, R7, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 |
| 10 | 10pF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 |
| 10 | 10uF | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C21, C22, C23, C24, C25, C26, C27, C28, C29, C30 |
| 9 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C12, C13, C14, C15, C16, C17, C18, C19, C20 |
| 7 | 10K | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8, R9, R22, R23, R24, R25, R26 |
| 4 | V53C16258H | VLB:SOJ-40_10.16x26.00mm_P1.27mm | U3, U4, U5, U6 |
| 3 | 75R | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3 |
| 3 | FerriteBead | Inductor_SMD:L_0805_2012Metric_Pad1.15x1.40mm_HandSolder | FB1, FB2, FB3 |
| 2 | 150R | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R21, R27 |
| 1 | 100pF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C11 |
| 1 | 14.318MHz | Crystal:Crystal_HC18-U_Vertical | Y1 |
| 1 | 27C020 | VLB:EEPROM_combo | U2 |
| 1 | 7404 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | U8 |
| 1 | 7408 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | U9 |
| 1 | 74LS245 | Package_SO:SO-20_12.8x7.5mm_P1.27mm | U1 |
| 1 | 86C765 | VLB:QFP-208 | U7 |
| 1 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1 |
| 1 | IRQ9 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | JP1 |
| 1 | LOGO | VLB:prometheus_logo | G*** |
| 1 | VGA | VLB:DSUB-15_female | CN1 |
| 1 | VLB_slot | VLB:BUS_VLB_Board | SL1 |
Questions
How big is the Virge vlb PCB?
It measures 240.5 × 69.4 mm and has 4 copper layers, 1.61 mm thick.
What parts does the Virge vlb use?
75 parts, built around the 74LS245SC. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Virge vlb KiCad files?
From the computerguy096/Prometheus-VLB repository on GitHub, at the commit this page was made from: the board is kicad/virge-vlb.kicad_pcb and its schematic kicad/address.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Virge vlb design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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