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| Miro Prisma II Plus Nubus Graphiccard ... |
Posted by: franklyn on 2025-09-24 10:09:07
I have a Miro Prisma II Plus, but I can't get it to work. I'm certain it's faulty. My NEC MultiSync 1970NX monitor supports sync-on-green, but I'm not getting any image. The graphics card should work with this monitor. I installed a composite sync to H/V sync converter on the graphics card, and the monitor powers on (the activity LED turns green), but the screen remains black – no RGB signal. The monitor's control panel shows the screen resolution that the card is capable of. So, the question is: what component on the graphics card is faulty? The IMOS G300 chip is quite expensive, and since @Bollle has published the entire GAL code, could I try swapping out the GAL chips one by one?
Does anyone have any ideas on what I should do? |
Posted by: franklyn on 2026-02-09 10:07:05
My graphics card isn't working and I'm trying to figure out why. The entire card uses high-speed 74-series chips. This socketed 74LS258 chip doesn't seem right to me. Otherwise, it's all HC or even F-type chips. Especially since this chip is socketed, which it shouldn't be.
Could someone who has a similar card check what kind of chip is originally installed? |
Posted by: Bolle on 2026-02-09 10:23:05
It's a 74LS258 on my cards too... also made by TI like on yours.
Looks like the one you've got is the original card.
I've got a monitor that supports the signal coming out of those cards as well as a DIY adapter. I can test your card if you want to send it over. |
Posted by: franklyn on 2026-02-09 10:41:46
Yes that is great. I made a H sync and V sync mod but that can easy remove. Send me your Address and I send you my card. There's no rush, everything has time ... |
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