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