Overclocked Deluxe - limited success

Well, I tried overclocking the Asteroids Deluxe board and here's what I've
found. I cut the trace between the CPU and the solder points so I'm not
increasing the clock to any other circuitry - only the processor. Then I
jumpered pin 37 of the CPU (clock) to pin 14 (6Mhz), pin 13 (3Mhz) and
eventually back to its original home at pin 12 (1.5Mhz) on chip C3.

@ 3Mhz - I get 5 high tones then 1 low tone, and this cycle completes. I
don't have a diag manual for Asteroids Deluxe. Anyone know what this
means? RAM Error perhaps?

@ 6Mhz - Nothing happens.

I'm not sure what the problem is, but I have a few hunches:

* How fast can the 2114s on this board actually run? Is 6Mhz too fast for
them to keep up? Hm.... 6Mhz=166ns if it can do a SRAM every clock. Is
this possible? I've found some 2114s that are rated to 200ns. Is it
worthwhile to swap them out?

* Are there any other circuits that are connected to the data/address bus
that might also be speed sensitive? The vector SRAM?

* Maybe the CPU can't keep up?

Any help would be greatly appreciated...

-->Neil

-------------------------------------------------------------------------------
Neil Bradley Play a song wrong once and it's a mistake.
Synthcom Systems, Inc. Play a song wrong twice and it's Jazz.
ICQ #29402898

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Received on Thu Apr 26 16:46:12 2001