2.5″ 44PIN IDE to 3.5″ 40PIN PCI adapter

Just another quick one:
I wanted to use a small flash IDE in a desktop PCI. Unfortunatly those devices really aren’t meant to be mounted in an ATX case, so I wound up a small adapter. The power for the flash HDD comes either from the PCI port or an external source. Kicad project files and gerbers are attached, in case you want to replicate this project ๐Ÿ™‚


Retro Chip Tester Professional

Just a quick note: If you’re testing old chips regularly you might want to have a look at the Retro Chip Tester Professional!

(This article isn’t sponsored, I’m just amazed by this device ๐Ÿ™‚ )

PS: The first test was successful, woohoo!


I put the RCT in a fancy housing:

You can get the housing at Mouser. But you have to customize it yourself ๐Ÿ™‚

I also replaced the LCD with an OLED.

The ports and switches on the backside are mounted with several adapters und pcbs:

The SD card pcb was glued in place with a 3D printed block underneath to support it. That’s a bit unfortunate, but the pcb itself has no mounting holes.

It’s flipping cute

I programmed a little game just for fun for my mini pc ๐Ÿ™‚

It is a cute little puzzle game with the “Lights Out“-mechanic. The game needs about 1MB of RAM and a VESA2-capable video card. It attemps to auto config a sound card for 16bit sound and MIDI music. It is written in C++ and was compiled with djgpp.

Furthermore I designed it to fit on a single 3.5″-diskette because why not ๐Ÿ˜›

Download: Here

PS: The game runs on MSDOS5+, Win95, Win98 and maybe under WinXP


I saw TheRasteri’s video about a mini PC the other day and fell in love with the idea – so I built my own ๐Ÿ™‚

The video in question:

And that’s my take on the idea:

Curvy yellow fruit for scale

I got a somewhat good deal on a mainboard from the UK, took some measurements and build a face- and backplate for the casing. The clunky power switch and overall design tries very hard to look like a retro PC, haha ๐Ÿ˜€

CPU: Embedded low-power onboard VIA Mark 533 MHz
RAM: 133 Mhz SDRAM 144-pin SODIMM 256MB
HDD: 2GB CF-Card
I/O: 2 x USB 1.1; 1x Gameport; 1x Line Out; 1x HDMI out; 2x PS/2; 1x VGA
GPU: VIA Mark CoreFusion VRAM 32 MB
Sound: *wink* *wink* Avance Logic ALS100 Plus+ PnP OPL3 sound card for PC/104
Power: 5V@4A

The decal on top is from this dude, who does awesome repro stickers: Geekenspiel (@geekenspiel) โ€ข Instagram-Fotos und -Videos (it covers a blemish in the casing ๐Ÿ™ )

Avance Logic ALS100 Plus+ PnP OPL3 sound card for PC/104

Hey there,

I’m currently building a tiny DOS gaming PC and needed a sound card for it. Unfortunatly there aren’t many PC/104* sound cards available so I spun up my own.

*= PC/104 – Wikipedia, basically a form factor standart

Since I wanted a sound card that was compatible with most standards so I can play as many games as possible with it I desided on the Avance Logic ALS100 Plus+. The IC is pretty well documented what made designing the sound card much easier.

It’s features are:

โ€ข Adlib
โ€ข All Sound Blaster Pro applications
โ€ข All Sound Blaster 16 applications
โ€ข PC Speaker
โ€ข Sound Blaster ADPCM
โ€ข Yamaha OPL3 FM Synthesizer

That’ll cover every game I’m interested in. The PC speaker is mixed in with the audio out by the IC, that’s pretty cool.

The hardware specifications of the new sound card are as following:

Hardware specifications
โ€ข Software selectable DMA lines (0, 1, 3)
โ€ข Software selectable interrupt lines (5, 7, 9, 10, 11)
โ€ข PC/104 ISA Plug and Play bus interface
โ€ข DMA interface with FIFO
โ€ข Enhanced Game port
โ€ข 8-bit or 16-bit stereo digital audio from 4 kHz to 48 kHz
โ€ข 3D Sound Effect Processor
โ€ข FM/wavetable synthesis via OPL3
โ€ข Wavetable connector
โ€ข Stereo Line-Out

Design and development

If you’re just here for the design files and aren’t interested in the failures I’ve had designing the sound card just skip to the end ๐Ÿ™‚

At first I took the specifications directly from the PC/104 consortium for the measurements: PC/104 – PC/104 ConsortiumPC/104 Consortium (pc104.org)

Then I read the manufacturer’s design sheet to build a sound card for the ALS100 Plus+ and added some minor noise cancellation.

First fail:

Yeah well, the IC is a bit bigger than a PQFP-100 (10% bigger to be exact). Meh. I tried to shorten the legs but ultimatively ordered another PCB. Bummer.

Second fail:

If you thought I would learn from my first mistake – think again! Yeah, so the OPL3 is also wider than a normal SOIC-24. This time I shortened the legs and soldered it down and went to testing (I shifted the IC down in the photo to better visualize the difference).

Third fail:

8bit- and 16bit-audio worked straight of the box so was the PC Speaker, but the FM synthesis was garbled. Staring at the schematics revealed another pretty stupid mistake:

If you havn’t spotted it yet: I switched around the adress lines. I cut the traces on the pcb and rewired them and FM synthesis was finally working.

Fourth fail (more like a foreseen issue):

There was a faint hum in the audio when plugging in a wavetable daughterboard. The soundcard has a digital and an analog ground which are connected at one point:

That’s fine and dandy – but the wavetable did just the same, so it created a ground loop. I removed the resistor on the sound card and the hum was gone ๐Ÿ™‚

The dimensions for the wavetable daughterboard are approximately like this:

While testing I used a Dreamblaster X2 which fits nicely. Also pictured: The fix for fail #1 and an OPL3-clone.



Gerbers: Download
Schematics: Download
iBOM: Download
Drivers: Download
kicad symbol and footprint of the PC/104 board: Download
BOM* with links to mouser.com: Download

*= Missing from BOM:
โ€ข PC104-Connector, available on mouser.com
โ€ข OPL3, available new old stock from various suppliers
โ€ข ALS100 Plus+, unfortunatly EOL since the late 90s, so you have to desolder it from a working sound card.

VRC4 repro questions & answers

Since the most questions people send me are about VRC4 repros I think its handy to have a dedicated post for some infos about them ๐Ÿ™‚

If you want to convert a VRC4 game into another you need to rewire the VRC4 in some cases. Have a look at this chart:

Any VRC4 to VRC4b
Lift pin 3 of VRC4 (skip if coming from a VRC4a)
Lift pin 4 of VRC4
Solder pin 3 of VRC4 to PRG pin 11 (skip if coming from a VRC4a)
Solder pin 4 of VRC4 to PRG pin 12
Any VRC4 to VRC4c
Lift pin 3 of VRC4
Lift pin 4 of VRC4
Solder pin 3 of VRC4 to PRG pin 6
Solder pin 4 of VRC4 to PRG pin 5

Any VRC4 to VRC4d
Lift pin 3 of VRC4
Lift pin 4 of VRC4 (skip if coming from a VRC4a)
Solder pin 3 of VRC4 to PRG pin 9
Solder pin 4 of VRC4 to PRG pin 10 (skip if coming from a VRC4a)

Any VRC4 to VRC4e
Lift pin 3 of VRC4
Lift pin 4 of VRC4
Solder pin 3 of VRC4 to PRG pin 10
Solder pin 4 of VRC4 to PRG pin 9

Any VRC4 to VRC4f
Lift pin 3 of VRC4
Lift pin 4 of VRC4
Solder pin 3 of VRC4 to PRG pin 12
Solder pin 4 of VRC4 to PRG pin 11

If you don’t know what VRC4 board revision you have and the game you’re planing to do, have a look here: https://wiki.nesdev.com/w/index.php/Talk:VRC4

Please note that the letter after VRC4 does not mean a revision of the IC but rather revision of the PCB!

You rewired everything according to the chart and the screen still looks garbled?
You may need to remove or add some components to the PCB, namely a 1K resistor, a 1N4148 diode a 2K*8 SRAM 150ns (or faster) IC and a ceramic capacitor.

The SRAM needs to be pin kompatible with the MB8416A-15LZ:

These are the components that need either be removed or soldered in:

Games needing these components:

  • Crisis Force
  • Ganbare Goemon Gaiden 2: Tenka no Zaihou
  • Gradius II
  • Parodius Da!

Games that need these components removed:

  • Bio Miracle Bokutte Upa
  • Racer Mini Yonku: Japan Cup
  • Teenage Mutant Ninja Turtles I & II
  • Tiny Toon Adventures
  • Wai Wai World 2: SOS!! Paseri Jou

I think that should cover all questions ๐Ÿ™‚ If not, just drop me a mail through the contact form, I’m always happy to help,

PS: Feel free to copy and share the info ๐Ÿ™‚