SuperFX overclock

[fahlim003]

I recently attempted the replacement of the crystal oscillator on a SuperFX SNES pcb, specifically Stunt Race FX. I followed the method described and illustrated here:
http://forums.benheck.com/viewtopic.php?t=7680&start=0&postdays=0&postorder=asc&highlight=

I got the 18pf capacitors however I used a 25mhz oscillator. First, I soldered in the new oscillator and tested it and it worked fine although I could not tell much had improved. I then put on the capacitors and from there my cartridge glitched up. The video was completely scrambled while the audio was intact. Once in a race the controls ceased to function at start was also an issue.

I removed the caps and all was well but still the net gain of improvement was negliable although it seems others have no need for caps either.

Basically, anyone else who has done this would be whom I'm speaking to. What sort of improvements did you see when you replaced X1? I suspect as addressed elsewhere, the game simply runs smoother, not faster. Parts with slowdown are lessened but the general speed is not improved or exceeded from the previous.

[Drakon]

I recently did a very different type of overclock mod for starfox 1. I bypassed the entire clock circuit and fed a 27 mhz crystal oscillator pulse directly into a super fx 2 chip with a starfox 1 maskrom soldered on. The framerate difference is massive the game is so much better at this speed. I've never tried overclocking any other super fx games.

[ooXxXoo]

Roviby64 is the master of the overclocks..He wrote some of the early tutorials for systems such as the NES/SEGA/TG16/SNES/N64 among others...

Here's his take on some SNES games for example:

http://www.sega-16.com/forum/showthread.php?18289-Super-FX-overclocking



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[Drakon]

Roviby64 is the master of the overclocks..He wrote some of the early tutorials for systems such as the NES/SEGA/TG16/SNES/N64 among others...

Here's his take on some SNES games for example:

http://www.sega-16.com/forum/showthread.php?18289-Super-FX-overclocking



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yeah roviby64 gave me the idea of using a crystal oscillator. Bypassing the hex inverter circuit and wiring the clock straight into the super fx 2 chip was my idea though. It was a little risky but turned out to be the solution to getting starfox overclocked on more powerful super fx chips.

Also installing a starfox 1 eprom / maskrom onto a stunt race fx / doom cart was a joint venture between me and doug. I'd say doug gets most of the credit for this part of the mod considering he did the eprom wiring. I basically told doug I wanted to see if it was possible and paid him to build me these carts since he was making starfox 2 carts anyway.

[Drakon]

Testing is done game 100% works at 27 mhz

http://www.youtube.com/watch?v=tOU2GikRRY8&feature=channel_video_title