sluggish Micro

[bigkim100]

I recently bought a arcade machine from the late 80,s, early 90,s. It consists of a large, multi-pin microprocessor, and a memory chip. All chips have had their ID#s obliterated.
Heres the question:
The unit seens to be "stuck"...not doing anything, until I place my finger across the leads of the crystal of the micro. I can then advance the game a "line"at a time.
In other words...if the game is supposed to play a tune bleep, blop, blorp , bloop, I can simulte this by placing and removing my finger from the crystal leads: bleep(touch),blop(touch),blort(touch)bloop(touch). Does this mean that the crystal is defective?...the crystal needs capacitance between its leads?.....whatcha think?
Thanks

[dacflyer]

can you scope it out ?

do you have another crystal thats close to the same value to try ?
doesn't have to be exact...which game is it exactly.. i used to work in the industry,,,maybe i can get you a schematic on it ...

do you have location numbers on the parts ?

[philba]

Look to see if the load caps for the crystal are broken. Look for broken traces. If it's a cmos chip, floating inputs can behave that way when touched - it's probably seeing a 120 hz signal.

What is the specific game? There are a lot of sites on the web for keeping them running.

Can you post a good quality picture of the micro & support chips? It may well be possible to ID it from pinout alone.