VOGONS


First post, by lowlytech

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I have a STB voodoo3 AGP card that will post, however after a few seconds the screen will blank out, after a few more seconds it will come back. So it is almost like it just looses sync but keeps running so it isn't freezing up completely. I have looked extensively for loose solder joints, particularly focusing on pins 13 and 14 and bypassed some of the ferrite chokes on the board without a change in behavior.

Could bad ram cause this behavior? I usually relate bad ram to garbage characters on the screen, which when this card is displaying an image, it looks perfect, so I don't think RAM is the issue. I fear it may be the GPU itself, but was checking if anyone here had another idea to try.

Thanks.

Reply 3 of 6, by lowlytech

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Wow, i have left this card connected to my NEC multisync 75 for about 15 minutes now, and it has not blinked out once. Ironically i would have ended up connecting this to a crt when i thought I had it finished, but i genuinely thought this video card was toast and didn't plan to even use it since i do all my testing and prep on a LCD.

Thank you so much Shamino, you made my day.

Reply 4 of 6, by lowlytech

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Well spoke too soon. I had previously bridged or bypassed one of the L ferrite beads?? In troubleshooting last time i had the card out and i know this didn't change a thing with the LCD monitor i test with, however when i tried on a crt this time around the system seems perfect. I just removed the L5 bridge and low and behold the card is now blinking in and out on the CRT. Can someone tell me what L5 is and where to order one?

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Reply 5 of 6, by rasz_pl

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You might have problem with power on the Voodoo, ripped/leaky capacitors?
All the L are filters (together with capacitors near them), they cut out high frequencies (harmonics). You would not have a proper picture at all if one of them was damaged (open).

Instead of guessing its best to slap an oscilloscope on VGA signals and check levels, frequencies and consistency (H V syncs).

Reply 6 of 6, by lowlytech

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Not sure if this will attach and play properly, but here is a short video of what it is doing now on the CRT even after I shorted L5 back like it was when it was working. Forgive the background, my son was playing the arcade off to the side.

https://drive.google.com/file/d/149MXss6eDf29 … iew?usp=sharing