Well I guess that's 2 endorsements for the Nvidia Quadro NVS cards. Thanks Scataphagos and bighog, I will pursue that avenue on future rigs, or if I totally strike out here with the Radeons. Just to recap, I'd been using the VTek Radeon X1300 dual heads (2 of them, so 4 monitors total) for 5 years with no problem. One morning I wake up and I've lost a monitor. After switching some things around I learn it's not the monitor itself, but just the one port on the one card that's the problem. So my instinct was to simply find an exact replacement for the card. Easier said than done, 5 years after initial product release. I've received 2 new cards that were not what I ordered, and I have a 3rd coming by Tuesday that hopefully will be right. I'll wait til then before going under the hood and trying everything out. I'll post an update. Thanks again for everyone's input and advice.
Update: I put 2 new (refurbished) cards in today. The dual head PCI card works, the single head PCIE16 DMS with the splitter does not. So, having this new one plus my other card that always worked, at least I'm back to 4 monitors again. I may try some other things with the PCIE16 card, or else swap it with another single I picked up for $25, just to add 1 more monitor.
That your X1300 is a "3rd party" version makes compatibility with other cards more suspect. Best would be to get however many you need of this same model and brand.
Thanks. ... Exactly. Well, magically when I installed the driver for the 2nd "new" card (the PCI dual head) all the monitor slots showed up in the setup app! So I'm pleased to report that at least for now I have the ability to run 6 monitors. Got 5 hooked up live ... found a 6th to match my Samsung 204B's on Ebay just in case I decide to sink more $ into this legacy system, which I'm not sure I want to. Thanks again to all of you guys.