Help with Radius Thunder IV GX 1600

[soundworks]

Just popped this one into my Quadra 840AV which is working great with a Precision Color 8 at 1152x870 (thanks to @joshc and this thread by @jmacz and @Phipli) -- I'm planning to move the PC8 to my IIci... Was hoping to run the Thunder in the Quadra at 1600x1200... but seeing these weird lines. Maybe someone here will know what might be going on? I confirmed with MrFlash that it's up to date. Have been running Dynamic Desktop 3.3, and just downloaded RadiusWare 4.0 via a post from @olePigeon but am dubious that the driver is the culprit... Would appreciate any thoughts!

I did include one shot at 640x480 where the lines are less pronounced than at higher resolutions. I think the other one of the menu bar is at 1024x768.

 

[Unknown_K]

RAM chip issues probably. Check if any of the VRAM chip pins are mangled or disconnected or shorting with another pin or if any chips are hot.

 

[soundworks]

i took a bunch of high rez photos and looked but am not keen enough to detect anything visually

 

[soundworks]

but good to know it seems like a RAM issue, thank you.

 

[jmacz]

Yeah I would concur given the consistent spacing that it’s a memory issue.

 

[soundworks]

Super helpful!

 

[olePigeon]

Does the old "stacking RAM chips" trick work with video RAM? Something we used to do in the 1980s with Apple IIs and arcades.

Could he just buy 1 VRAM chip, then stack it on the other chips one by one until the problem goes away?

 

[Phipli]

i took a bunch of high rez photos and looked but am not keen enough to detect anything visually

I'd suspect a lose pin on a VRAM chip, or possibly more likely (given frequency of it happening on various cards I've owned), a lose pin on the RAMDAC chip. A third option is damage to a trace or corrosion, most likely on the reverse of the card as that is where they get scraped when dumped in a drawer with other cards.

My first test after a visual inspection would be to use the tip of an... (/me checks what country you live in)... exacto knife to very gently touch each pin on the RAMDAC and see if any of them a not stuck down.

You'd be amazed at how frequently this is the issue on cards.

If you find one, check the ones around it because they often come in groups. Mark where they are with a pen on the top of the chip. You'll need to reflow the solder. Best done by coating the pins with no-clean flux, and then using a soldering iron with no solder on it to just stroke the feet of the pins with a wipe away from the chip. Clean with alcohol and a... cue tip... and then test again with the tip of the exacto knife. Repeat if they're still not fixed down.

If you don't find any pins that are lose on the RAMDAC, check the VRAM chips. It might help to get a plastic pen (no metal showing, don't use a pencil) and tap / poke chips while the card is running and see if you can find an area of the board that when you touch makes the image improve / get worse. If you find somewhere that poking changes the image, that is likely the area to start searching for damage or lose pins in.

Good luck! Let us know how it goes and btw, I'm very envious of your card - I wish I had one of those.