Lopo wrote on 2026-05-04, 06:37:

Just sent my first PCB revision to fabrication - a reverse-engineered duplicate of the DataExpert 367C motherboard with UniChip […]
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Just sent my first PCB revision to fabrication - a reverse-engineered duplicate of the DataExpert 367C motherboard with UniChip U4800-VLX chipset.
The challenge: there's no datasheet for the U4800-VLX anywhere. All 160 pins had to be mapped from scratch using PCB scans, photos, multimeter tracing, and cross-referencing with other designs (Groza's OPTi 495XLC SBC, Skiselev's SARC RC2016 386SX board).
This v0.1 is essentially a 1:1 copy to verify the reverse engineering is correct. If it works, future revisions will diverge with improvements (ATX power, VLB slots, expanded cache, etc.)

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Fingers crossed! 🤞

This is simply amazing, I commend you for your hard work and look forward to an ATX version.

Worked on my video card Memory Tester Launcher. Boots from a USB stick. It’s just a simple BAT file but consolidates all the memory testing tools in one place and makes sure logs are easy to access.

AndrettiGTO wrote on 2026-05-04, 00:15:

Susanin79 wrote on 2026-05-03, 22:05:

Tried to test an IBM PGA card, no luck so far. IBM diagnostic disk able to see it in a list, but failed with the diagnostic.
Will continue with the close inspection under the microscope and ICs deoxit.

Not many of those around and it's a sweet card to have! Maybe try in in CGA emulation mode (Jp W1 @ 1-2) first to see if it passes.

No, I tried this mode. At the boot PC complain about the video mode (one long, two short beeps). Final picture looks strange, the simple blue picture with some tiny pattern, sometime I can see the noise but then it just reset to this blue screen.

zuldan wrote on 2026-05-04, 08:32:

Worked on my video card Memory Tester Launcher. Boots from a USB stick. It’s just a simple BAT file but consolidates all the memory testing tools in one place and makes sure logs are easy to access.

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Nice one. But "Voodoo 2"? Is there a memory testing utility for Voodoo2?

H3nrik V! wrote on 2026-05-04, 11:12:

Nice one. But "Voodoo 2"? Is there a memory testing utility for Voodoo2?

Unfortunately not. That’s just Witchery. Maybe I should call it Video Card design diagnostic tools.

Susanin79 wrote on 2026-05-04, 09:30:

AndrettiGTO wrote on 2026-05-04, 00:15:

Susanin79 wrote on 2026-05-03, 22:05:

Tried to test an IBM PGA card, no luck so far. IBM diagnostic disk able to see it in a list, but failed with the diagnostic.
Will continue with the close inspection under the microscope and ICs deoxit.

Not many of those around and it's a sweet card to have! Maybe try in in CGA emulation mode (Jp W1 @ 1-2) first to see if it passes.

No, I tried this mode. At the boot PC complain about the video mode (one long, two short beeps). Final picture looks strange, the simple blue picture with some tiny pattern, sometime I can see the noise but then it just reset to this blue screen.

IIRC there are no DOS/BIOS modes for that card, so you need a primary video card still, would suggest MDA .

Susanin79 wrote on 2026-05-04, 09:30:

AndrettiGTO wrote on 2026-05-04, 00:15:

Susanin79 wrote on 2026-05-03, 22:05:

Tried to test an IBM PGA card, no luck so far. IBM diagnostic disk able to see it in a list, but failed with the diagnostic.
Will continue with the close inspection under the microscope and ICs deoxit.

Not many of those around and it's a sweet card to have! Maybe try in in CGA emulation mode (Jp W1 @ 1-2) first to see if it passes.

No, I tried this mode. At the boot PC complain about the video mode (one long, two short beeps). Final picture looks strange, the simple blue picture with some tiny pattern, sometime I can see the noise but then it just reset to this blue screen.

You should check it this thread, good information there.
https://forum.vcfed.org/index.php?threads/ibm … ars-dead.63859/

Creating a simple EPROM emulator for old-school projects:

I still make a lot of special purpose embedded systems, these are still mostly "old school" as I have *many* tubes of old-school parts, 40-pin CPUs (6809, 8051, 8085, Z80, 6800 etc) and 28-pin EPROMs and static RAMs.

But I really don't like "burn and learn" debugging, burning EPROMs, trying code, then erase/burn to make changes. I have a few "dev" boards made up with debug monitors and loads of RAM, but often I still have to debug on the actual special purpose board I'm building.

Back in the day I created "QDRE" (Quick and Dirty Rom Emulator) which had a RAM wired to a socket to "look" like a ROM, and a board attached to PC parallel port with counters and buffers to be able to load that RAM (on a little board with flying power leads) which I could then move to the system under test... Worked well, but it needed a DOS PC to perform "non-standard parallel port functions" which I have fewer of now, and they are big to move around.

So I decided the make a much more portable/faster version ... Back in the day I had made and sold an 8032 board called the BD52 - I had one which was "almost complete" so I decided to do it on that platform.

The reason it was "almost" and not "fully" complete is it used a PAL for various funcitons ... but I no longer have a PAL programmer. It was fairly simple to make a little daughter board that fit the PAL socket to configure the system as I wanted.

It also used "thin" RAMs who's sockets didn't line up with standard "fat" 28-pin EPROMs.

Scrounging through my junk bin I found a strip of PCB which had connected rows of pins for both standard and thin width. I was able to cut a bit and make a "THIN2FAT" pin spacing adapter.

I used a bit of the same board and one of the thin RAMs in between the standard EPROM pins, with a 3 jumpers and a few pull-up resistors added on the end to configured it as an 8k, 16k or 32k RAM or ROM pinout.

(I have to say hand placing and soldering this little board now that I'm old and have vision issues was NOT easy - fortunately I have a 7x over the head magnifying visor ... still spend a few hours on it)

The good news is that everthing came together and works perfectly.
--Attached pics--

EE1 - top side of RAM<>EPROM board

EE2 - bottom of ""

EE3 - RAM<>EPROM board in a ZIF socket on the THIN2FAT in BD52.
You can also see the daughter board I made to replace PAL.

I found a "normal" socket which the emulator pins fit into, which in turn has the right size pins to plug unto a "machine screw" socket (two black lines just above ZIF) - this gives me a perfect way to plug into the target system, and makes it easy to replace if it should get damaged!

"Repaired" an optical drive that wouldn't eject the tray with no disc inserted.
Tourned out to be an old harded rubber belt not able to transmit enough force from the motor to the drive mechanics to separate the magnet in the center of the drive spindle from the metallic plate above it.
That magnet-plate combination holds the disc in place on the spindle while spinning. With a disc inserted there's a certain amount of space between these parts which makes overcoming the magnetic force and hence separating them a bit easier allowing ejection eventually. No separation means no lowering of the internal drive mechanics and no giving free of the disc tray for ejection.
Solved for now with a belt from another defective drive.

I scavenged at a local thrift store and picked up a bunch of XP-era shooters that I never heard of. The kind that you'd see in the value CD-ROM racks.

Spent time collecting old driver stacks from Archive's uploaded CDs, because I'm rather particular about versions and optimisations.

Also started dipping my toes into the retroscape by reloading software such as this AMD Athlon 64 marketing / official AMD screensaver..

Dug out my old Wii and scrolled through all the miis my family made, honestly so surprised it still works flawlessly after all these years.

Juggling video cards around in my systems. Wanted to try my 9700 Pro in my P2B-DS system, but the passive Zalman cooler on it comes too much above the AGP slot and fouls the Slot 1 slots. So, I grabbed the GF3 Ti200 out of my Slot 1 Tualatin system and thought hmm....

So obviously this is a bad idea for multiple reasons, not least of which is the PSU is the original from when this Baby-AT case had a P166 in it. On the other hand, I managed to cram it in there, it works (for now) and no one stopped me. 😤

Bought a revision 1 Wii to homebrew on.....
I think I probably made a mistake tbh, at first I thought it'd be funny to try to daily-drive the Wii with NetBSD but very quicky I realised that just isn't very feasible.

Granted there's probably some homebrew that might make it worth using, but I haven't really found much right now-

There was some emulation of older consoles IIRC. That was the only thing really that caught my eye, but some years since I looked into it.

Does anybody know the right size for a decent Socket A cooler fan? Specifically Athlon XP chips.

RetroLizard wrote on Yesterday, 22:47:

Does anybody know the right size for a decent Socket A cooler fan? Specifically Athlon XP chips.

Might help to know the board, some have no clearance and need the bare minimum 60mm square one with screamer fan. Probably 30mm high with a 15mm tall fan is smallest you want to try if you're looking at a pile of randoms.

BitWrangler wrote on Today, 00:10:

RetroLizard wrote on Yesterday, 22:47:

Does anybody know the right size for a decent Socket A cooler fan? Specifically Athlon XP chips.

Might help to know the board, some have no clearance and need the bare minimum 60mm square one with screamer fan. Probably 30mm high with a 15mm tall fan is smallest you want to try if you're looking at a pile of randoms.

Here's a picture of the fan I want to replace. It's too noisy.

RetroLizard wrote on Today, 00:51:

BitWrangler wrote on Today, 00:10:

RetroLizard wrote on Yesterday, 22:47:

Does anybody know the right size for a decent Socket A cooler fan? Specifically Athlon XP chips.

Might help to know the board, some have no clearance and need the bare minimum 60mm square one with screamer fan. Probably 30mm high with a 15mm tall fan is smallest you want to try if you're looking at a pile of randoms.

Here's a picture of the fan I want to replace. It's too noisy.

Have you tried cleaning inside and topping up with sewing machine oil?

My approach is to first clean the blades and housing with wet wipes. Then use a loose razor blade to carefully cut old adhesive and lift the old sticker/seal - if an original sticker is removed in one piece it might have cosmetic value for wall art pieces.

Then use a cocktail stick or tooth pick to lift out any black residue - I don't use any solvent in this step because I find dry residue easier to remove than wet residue. As the structure is not airtight, I use a blower to try and push any more residue from bearings into the well - this step might be pointless but I do it just in case more residue can be found.

Next add a drop of oil and blow on the blades to gently turn them. Repeat until it's spinning silently. I simply wipe off any excess machine oil using wet wipes and leave to dry before resealing - maybe dampen an old wet wipe with isopropyl alcohol, but I don't want anything contaminating the oil I just added.

Old advice was to reseal using the original sticker, but I find the decades old adhesive too dry to reuse. I reseal with builders aluminium tape - the type used to waterproof house insulation. Ideally, you don't want adhesives dissolving into the oil, and you don't want oil dissolving the adhesive, so the method I presented can be improved upon.

Hypothesis: You can reduce noise levels by doing the same to new fans.

MattRocks wrote on Today, 05:08:

Have you tried cleaning inside and topping up with sewing machine oil? […]
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Have you tried cleaning inside and topping up with sewing machine oil?

My approach is to first clean the blades and housing with wet wipes. Then use a loose razor blade to lift the old sticker/seal, and use a cocktail stick to remove any black residue. I use a blower to try and push any more residue from bearings into the well, because the well isn't airtight - this effort might be pointless. Then add a drop of oil and blow on the blades to gently turn them. Repeat until it's spinning silently. Wipe off any excess machine oil using wet wipes. Leave to dry before resealing.

Old advice was to reuse the original sticker, but I find the original decades old adhesive too dry to reuse. I reseal with builders aluminium tape - the type used to waterproof house insulation. And, ideally you don't want adhesives dissolving into the oil so my approach can be improved upon.

Hypothesis: You can reduce noise levels by doing the same to new fans.

Oiling only really works on sleeve bearing fans, but those Athlon Socket A fans were usually of the ball bearing type. The bearings are sealed and cannot be re-lubricated, so when they're shot the fan is done unless you manage to get an exact replacement bearing, and in some cases they're just noisy even when new.