williams cyclone - fix

[qrz]

my arcade customer had me take a look at one of his pinball units today .

strange symptom as it seldom did the same thing twice upon pwr up..... ?

decided it must be a syscon issue . suspected a reset problem as it had some other random problems as well.

C30  ( 22uF @25v) is the C part of the RC time constant for the reset generator.
wasn't too surprised when it measured out at 15 uF  and an esr reading of 350 ohms .
replacing the cap eliminated the start up symptoms.
next issue was the knocker and ball launcher would alternately kick , then also noticed the "ferris wheel" wasn't rotating .
fault was traced to a missing 25v source . the ground sides of rect bridge br1 were open.
replacing the diode restored normal ops   

sure glad he had a schematic !!


qrz