TECH: MM intermittent ball launch problem. Solved!
beaver
Madness for a while. Since the solution turned out to be so generic, I
decided to post this note.
On an intermittent basis, the MM refused to launch the ball. When this
happens, the ball launch button IS flashing. I also changed the
configuration of the machine to allow ball launch with the right
flipper, and the same problem occurs. All switches and ball trough
optos work fine in switch matrix test, but I still changed the shooter
lane switch and diode just in case. Another symptom is that sometimes,
the auto plunger solenoid will fire once a second after the ball is
launched (no ball present in shooter lane), for up to~7 seconds, and
sometimes after launching the ball, I will get an undeserved
multi-ball.
Today, I resolved to solve the problem, and found it! One clue was
that I could smack the side of the cab with my flat hand, and it would
seem to help the ball launch problem. After half an hour of testing
the same old things, I noticed that I would hear a soft click after
smacking the side of the cabinet. With the coin door open, the click
was loud enough to hear. It turns out that the trough eject solenoid
was stuck in the up position on an intermittent basis (!). When this
occurred, it caused the balls not to slide over even though one ball is
in the shooter lane. The CPU was then confused, and refused to
activate the auto plunger. After enough punching of the launch button
or clicking of the flipper, the trough eject plunger would pop down,
and the balls would move over.
So I completely disassembled the ball trough and cleaned every part of
the trough eject solenoid, now it moves smoothly up and down. Ball
launches are now error-free. My MM is now 100% working. Yay!
Edward Cheung CARGPB26
Dgrant
beaver wrote in message >
> Today, I resolved to solve the problem, and found it! > So I completely
> the trough eject solenoid, now it moves smoothly up and down. Ball
> launches are now error-free. My MM is now 100% working. Yay!
>
> Edward Cheung CARGPB26
Congrats Ed! I, along with many of the people in this group know how
satisfying it can be to finally find a nagging problem. These problems, as
small as they may be, can seriously take away from the fun of the game due
to you obsessing about it while playing (at least for me). My nag was a T2
problem that lit multiple CPU lamps at a time. Finally turned out to be a
diode in the T2 skull was not wired in correctly.
Congrats again and enjoy your error-free gameplay!
Doug
just plain Rob
Very interesting reading. Thanks for the info...
Rob
RonKZ650
while. Good job.