Hi all,
I have lost the sound on my Bally Fathom.
The LED on the Squawk and Talk board is locked on.
The MPU is OK (7 flashes).
No sound but with the volume up there is a hum.
When I activate switches during a game I get an faint 'blip' sound.
I have re-seated the connectors on the S&T and J1 and J2 on the MPU.
From what I have read it seems like there could be a faulty component on the S&T board. Anyone have any ideas?
Sounds like a reset problem, this is from the pinrepair guides:
S&T Board Reset/Boot Problems.
The Squawk and Talk board is not unlike the MPU board. It too is a computer, with a reset section, and an LED which "flashes". The flashes determine if the board has a "boot" (turn on) problem. But before the board boots, it needs to "reset" (hold the CPU's /Reset line low until +5 volts can stablize, and then allow the /Reset line to go high and start the boot process).
Often this reset process never happens, and the S&T board never boots (LED locked on). Since there is no battery on this board, battery corrosion usually isn't causing any problems (unlike the MPU board!) But the reset section can have faulty parts. One common thing that fails is capacitor C1 (47mfd 16 volt). Replacing this part, or the reset transistors, can often solve a S&T boot/reset problem.
