nuBus video card not displaying properly.

[CelGen]

I found this 16 million color Apple branded NuBus video card and I really want to use it in my Mac II however it has this issue.

On every monitor I connect it to, I got no picture but when I hool it up to my 17" Apple display, I get this:

When I got it there was visual signs it had been in a pretty hostile environment. Some chips had corrosion on the leads, one of the crystals had rust on it.

Still, is this something along the lines of say a bad crystal or is the card plain and simply hooped? finding devent NuBus cards around here are surprisingly hard.

 

[Unknown_K]

No idea, I think that is a 640x480 card.

 

[Trash80toHP_Mini]

Judging from the date on the card, my guess would be 640x480 MaxRes too, but I haven't researched it. Might be a bad crystal since you're getting an almost legible display, but you'll need to wait for TomLee to show up or one of the MLA's other boffins.*

* IIRC, that was Brit slang for those magicians/sorcerers adept in the black arts of Electronics/RADAR/Electronic "Computing"/Code-Breaking and such at places like Bletchley Park, one of the pre-eminent Xerox PARCs of WWII.

 

[JRL]

I think something's wrong with the onboard VRAM. My IIci's Hi-Res vid card has the exact same issue (scrambled picture)

 

[CelGen]

I think something's wrong with the onboard VRAM. My IIci's Hi-Res vid card has the exact same issue (scrambled picture)

Usually when I have had an issue with vram I was getting pinstriping.

 

[Unknown_K]

I think something's wrong with the onboard VRAM. My IIci's Hi-Res vid card has the exact same issue (scrambled picture)

Usually when I have had an issue with vram I was getting pinstriping.

Pinstriping is the most common defect I have seen.

Since the card is rusty/dirty try washing it with some soap and water to clean that crud off, let it dry a few days, and try it again.

I suspect the RAMDAC chip is shorting or failing.

 

[CelGen]

I have washed it more than once using the same technique I use with motherboards which is put them in the dishwasher with the heater off and no detergents.

No success at all unfortunately.

 

[Osgeld]

to me it just looks like the timing is off, bad caps, rotten crystal or just a plain old wrong monitor could be it

 

[CelGen]

I'm thinking it's one of the crystals going bad. I'll see if I can scrounge up a similar one and if I'm still having issues I'm guessing the card is hooped.