First post, by christal87
I have just started to feel a retro fever a year ago again. One of my teenagehood's card was a V2. I used to play a lot of Glide titles, before switching to a GF256DDR that had HW T&L.
Bought a cheap noname (STB?) card here in Hungary from a well known source. It could be one those late 12MB V2s with 1Meg EDO DRAM chips. I bought this card with a slightly pinkish/purplish output. After creating a video file consisting of the SMPTE color bars and individual RGB color fills and a white one, went ahead and played it back using a dshow filter video playback utility on the card. The 10+ yrs old TFT monitor was too good to direcly eye out the problem. I suspected that either red is too much or one of the other two color signals (green) are weak. So hooked up the individual color tests again to a scope. Well wha'd ya know... All the outputs were just below 700mV, excluding the green color bursts which were under 400mV. I started to suspect damage to the output selector IC (PI5c3384), since this card has unpopulated TVS diodes. After measuring the output signals directly from the RAMDAC (ICS5342) green was OK, but still not up to the VESA standard somewhere between 0.7-1.5V. Yes, one of my S3 cards have an output just under 1.5! Went ahead and ordered both the output selector and the RAMDAC from UTsource, exchanged them and voila! It's good as new!
Anyone experiencing such symptoms on a V2 can grab these and with some proper soldering skills with a cheap, but temperature controlled chinese hot air station can fix it. Just watch out for the GNDs. You will have to apply the right amount of heat. My first attempt had the same problem and original glide drivers crashed right after loading Windows. Fastvoodoo drivers tend to crash when I started loading a game. It was just a floating ground. The card only has a single quartz attached to the RAMDAC. I believe every other clock is synced to the RAMDAC, so if you have a RAMDAC/xtal main clock issue it might act like this.
On the other hand, I have two other cards with freezing up or no display output. I still have to develop a better way to debug cards then mojo.exe and enabling logs with SSTV2 envvars to a serial port or using the donut and other demos. Especially a good EDO DRAM testing technique. Also I started to reverse engineer the working card to a KiCAD schematic diagram. It's still in the early phase consisting of only the output selector, RAMDAC and parts of the clock synchronization circuitry. Unfortunately I don't have too much time for a hobby nowadays...
Good luck to you all!