Star Tech Journal

GD
...;.._'TAR TECH JOURNAL
september 1994
WEAK FLIPPER SYMPTOM
THE 0PTO SOLUTION
Wayne Glover
State Sales & Service
Baltimore, Maryland
SYMPTOM
Have·you ever gone on a call to a
location where the players are
complaining about one of the
flippers becoming weak after a
few minutes of play?
You have checked the plunger
and link assembly for excessive
play or wear, looked for any me-
chanical binding and may go as
far as replacing the flipper coil.
Upon testing the flipper again,
you find that it still gets weak af-
ter a short period of time.
CAUSE
Well, we think we have found the
cause of this annoying little prob-
lem.
We took a look at the flipper opto
board with a 'scope and found
that the output of the opto was
oscillating.
REASON
The flipper is turned on and off
rapidly, causing the power wind-
ing of the coil to overheat.
The resistance of the coil in-
creases and the flipper becomes
weak. You will not notice it
working improperly because the
flipper does not drop out due to
the holding winding being turned
on.
11
•••
h lf
testing t e r1ipper
If you have a logic probe, or your
multimeter is equipped with one,
you can use it to check the out-
put of the opto.
ISOLATE THE SYMPTOM
again, you find that
it still gets weak after
A quick and easy method to de-
termine if the problem is in the
opto board is to swap it with th
one that is working.
If the symptom moves with the
board, then you have located the
culprit.
CONCLUSION
a
h
S
ort perio
time."
d f
O
Replacing the defective opto or
opto board, whichever you have
available to you at the time,
should get your flipper back up
to full strength.