So I got my hands on a Schneider Electric IMT23001 Analogue Multimeter. It does support Ohms, so what would I be looking for and what would show something's not right?

rasz_pl wrote on 2022-04-08, 03:32:

VirtuaIceMan wrote on 2022-04-07, 07:47:

Is there anywhere online where people do these sort of fixes or can be asked for help?

local hackerspaces are best bet

I think the same.
What also comes to mind.
These people know how to solder and fix things, too:
- Model builders (you know, r/c models, ship models etc) - know how to wire things, install motors, gears etc.
however, they aren't much into video games likely
- Radio amateurs (hams). Some are very skilled and have a good understanding about electronics in general, but maybe are decades behind at worst when it comes to digital stuff
- Retro gamers and their clubs/meeting places - more into 70s/80s consoles, but able to solder mod chips etc. also
- Arcade fans - know how to repair mechanical pinball machines and arcades (switch CRTs, make/fix cabinets), but aren't into precise soldering?

I'm sorry, that's all that comes to mind right now.
Whete someone definitely gets no help.. : computer shops
As strange as it sounds. Today's IT professionals have no understanding about electronic basics, I think. They're so out of this world. They only know software, protocols.
They won't fix anything. They will stare at the card (PCI? Huh? Must be worthless junk!), take the card, send it somewhere and charge money for it.
If someone's lucky, the card comes back - unrepaired. With only a minor extra damage.

Edit: Now that I think of it. There's another group I forgot about.
- Radio/TV repair shops - almost extinct, but those repair technicans of old had soldering skills, too. Even though SMD parts as we know it didn't exist yet in their time frame.

Edit: These are just some ideas, of course.
It would be best if the card finds its way into the hand of someone who knows what it is.
A serious person someone can trust, rather than a random person on the internet with only a postal box address.

So an electronics repair shop or a hackerspace really makes more sense, I guess.
The person in question should be accustomed to the parts on the graphics cards, at least.

So is there anything I can check/look for with a multimeter? Just to diagnose what might need replacing?

Did you ever get a solution? Having exactly the same issue.

88mphTim wrote on 2022-09-17, 02:15:

Having exactly the same issue.

"non-stop interference pattern across the screen"? can you make a picture of it?

No, I asked someone who fixes electronics but they never go back to me. It's for a project I haven't started yet so it's a while until I need it. If you find out anything yourself, please let us know 🙂

So I fixed it on mine by changing DVI adapter and I threw out the old one already do I can't reproduce. On mine there was a thin strip of darker pixels on the left side, and when anything white went into that darker area is streaked a wavy 'shadow' horizontally across the picture. So the walls, white lines on the track (in NASCAR Racing), the mouse pointer, etc, anything that went into that strip on the left streaked over on the right.

After changing DVI adapter that dark area on the left no longer exists.

I actually just found a picture, see attached. You can see the dark area on the left and the white wall also on the left streaking over on the right. In motion it looked like a wavy shadow streaking across. I'm assuming maybe there is some interference and my DVI adapter had poor shielding or something.

When I hear adapter I think passive. What you have is DVI converter, that means digitizing analog signal, scaling resolution, converting timings. Those have a strict list of supported resolutions/refresh rates and timing formats, anything outside will either not work or glitch. A lot can go wrong during conversion.

Interesting, but on mine the interference lines are diagonal across the whole screen. And if I swap cards they're not there with the same cable hence me thinking something is amiss on the card.

it can be something as trivial as different/non standard front/back porch width screwing your converter.

I'm just using VGA out to a flat screen LCD monitor at the moment

oh sorry, I thought I was still replying to 88mphTim 😀
so you have same picture defect on LCD? in all resolutions?

Yeah, when using NVIDIA NV1. When I use a different graphics card there is no artifacting

It took me a while looking at https://imgur.com/a/28nIV8o to spot it, at first all I saw was moire.
Might be bad power - you can be seeing beating of the supply voltage. Since the card has linear vreg (lm2941) the only chance of that happening is either broken output cap (mlcc, needs specific high esr for stability) or PSU 12V rail.
Or this card is just that bad at filtering VGA signal, those lighter streaks are barely visible on pictures.

btw Im a big fan of your 'Every PC Rally Game' series, let me discover few games I didnt know existed 😀

Thanks! I've paused the rally game comparison, to catch up on F1 games. But I'm about to launch something completely new related to Sega on PC.

Regarding your other points, I'm not very electronics minded so I'm a bit lost really.

tldr: try with different power supply, its a long shot. Other than that I would look for a hackerspace/radio amateur/electronics nerd with good gear and look at output signal with an oscilloscope. Put constant color screen on and check what frequency is the distortion, this should be the clue to its origin. Also check cards supply with oscilloscope.
another long shot is checking with another monitor

Time for a super-bump as I'm looking to finally capture from my Diamond Edge 3D 3240XL NV1 card soon (not the one that needs hands touching it, though I've not tried that approach yet!)

I've recently got an AV.io HD to make the captures super crispy. But this also enhances the interference...

I've Photoshopped this a bit so you can see it better. These lines whizz vertically up the screen. Switching to higher res (e.g. 800x600) does slightly different interference. Annoyingly it's almost negligible at 1024x768, but the games will only run at up to 800x600 and the polygons start flickering wildly if you change resolution whilst in-game...

If I change the refresh rate from Adapter Default (60hz) to Optimal (75hz maybe) then the interference is again minimised a bit. But then the games run too fast (great programming Sega!).

As mentioned before, other graphics cards don't exhibit this issue, so sadly it's something up with my Diamond Edge 3D 3240XL in particular.

I think I'll have to make captures with the card as-is for now, as I'm not sure I want a stranger to be resoldering/replacing parts before I've made captures, just in case something goes wrong!

Whew, it's been a while!

I was working on a totally unrelated card yesterday and it suddenly developed the same issue that this card had! It would get artifacts on the screen and touching the back would make them go away. I played around with it for a while and it seemed to actually be from SOJ memory chips that weren't seated fully in their sockets. I still had some other issues with that card so I looked at something that I'd never really looked at before: the solder joints on SOJ chips that aren't in sockets. When I looked at them through my microscope I realized there were tons of them that had visibly broken joints! I reflowed all of the joints on that card and it fixed most of the issues... but it still had some. I was tired of trying to diagnose that card but I had a MAJOR lightbulb moment when I remembered this poor old NV1.

If a floating (not connected) leg\pin on an SOJ memory chip could cause these weird artifacts that react to touch, then surely an SOJ chip with a broken solder joint could do the same?

Long story short... I used my hot air station and some flux and made an attempt at reflowing all of the pins on the two large chips on the NV1 as well as the joints on both sides of the soldered memory chips.

The result?

The stinking artifacts are gone! I fixed it! 🥳

I was able to load up the special Descent NV1 demo version and it was definitely working... because it ran pretty slow on a PIII 850. So, erm... success! I played through the first level of that game and it worked flawlessly (aside from some pretty significant slowdowns at times, but this IS an NV1...). The music sounded surprisingly great and the digital effects were awesome. This would have been a nice experience back in the day... if more games had made use of the NV1 it was definitely a cool package for someone with a mediocre CPU and no sound card.

At that point, I was quite pleased, but that was when I realized that populating the two memory sockets to bump the card up to 2MB was doing nothing. Windows was limiting my resolutions and dxdiag was reporting 1MB.

So... more troubleshooting ensued. Using my microscope I managed to find not one but TWO physically damaged components on the board! A capacitor near the BIOS socket that was cracked in half diagonally, and a 000 resistor pack not far from it that had a chip out of one side so that one of the leads was broken.

The capacitor was in a terrible spot between an electrolytic cap and the BIOS socket, which meant that the hot air station just wasn't cutting it... too much heat was going into surrounding components. The board was nice and hot at that point though, so I was able to just use my iron to remove the broken pieces of the cap, then replace the cap with one from an assortment I purchased last year (no idea what the original value was... I chose 330nf).

For the resistor I cut a teeny-tiny piece of stripped wire-wrapping wire, put a slight bend in it and laid it down on the side of the resistor pack that was broken so that it was touching the disconnected solder joints (the picture is before I soldered it). I blobbed a bit of flux on it to hold it in place, tapped each side with my iron and the bodge was in place and looking surprisingly neat. Nice!

I checked the card over thoroughly for any shorts or debris (having nearly invisible bits of wire near a card is a dangerous game) and it seemed okay so I put it into the computer and...... the dreaded beep of no video card. Blahhh...

But it was actually nothing. Turns out that one of the times I'd used flux and rinsed it with alcohol it had run down and created a little dried layer of gunk on part of the PCI connector. I cleaned that off and it booted fine. Whew!

I got into Windows, opened display properties aaaandd.... *drum roll*... I could select 1024x768 at 16bit color!! That res, 800x600x32bit and 1280x1024x8bit all worked perfectly! I fixed my NV1! 🥳 🥳 🥳

Much fist pumping ensued, then I loaded up NV1 Descent again, played through level 2 with the sweet GM tunes and digital effects blaring and plugging along in fully 3D-decelerated form on my NV1 on a system that'd run the game way way way too fast in software mode on a PIII 850. So, I guess adding a 3D card did make the game playable in a backward sort of way.

It's been quite a ride, but I'm looking forward to having this JUAN JRS-3DS100 in the collection in WORKING condition now. Oddly, the NV1 3D Shapes demo still does not work... maybe it really needs to be run on a slower system in Windows 95 or something. I don't know. The card is still missing its back plate due to being salvaged from a scrap lot almost seven years ago, so I'd love to get that replaced too, but more likely I'll just have to cobble a home made replacement.

Anyway, I'm really happy about this and there's something so cool about fixing a video card and then having a fully functional 2MB 2D card with a nice picture, a usable 3D accelerator (well, sort of), solid digital sound and decent sounding GM MIDI synth in just one card. Most of the time when I test video cards I don't get sound too. Good ol' Jensen may not have had a market-winning product on his hands with this, but I think it was pretty cool. 😁