Star Tech Journal

''REPAIR OF ROCK·OlA
DOLlAR BILL PROGRAMMERS"
S*T J
JUNE 1981
3
by Chuck Maier
There will come a time when your customers will complain about
being cheated on a dollar bill. Now we all know that a dollar is
only worth about 40¢, so what are they screaming for? But who
can afford to lose even 40¢ nowadays, so we're gonna tell ya how
to fix it up.
First determine that the problem is with the programmer. An
easy way to do that, is to momentarily short the yellow-green wire
at the white socket of the Buckpasser to ground. This is the same
effect as the vend relay in the Buckpasser energizing and it
should cause the programmer to operate and establish credits.
If you get credit every time, then the Buckpasser needs work
instead.
OK, you either get no credit or the wrong amount, so you're
gonna do all these things to the programmer to update it and
keep it working properly. On model #47875-A, used in machines
with mechanical accumulators, follow steps # 1 to #6. On model
#51610, used in 468 and 474 electronic credit units, add step #7.
OK, soldering irons up, begin!!
1. If the unit has a large grey motor without a label on it, replace
it with a Cramer motor (white label). These old motors tend to
lock up and you get no credits. New motor is Rock-Ola
#48117-1.
2. While you have the motor out, clean the motor switch sections.
Dirty switch contact can cause short credits, continuous
motor run or failure of the red relay to energize.
3. ADD a .047 MID @200V (Rock-Ola #47722) capacitor across
the triac (green-white wire to tan wire). This shunts motor
noise ( especially reverse) from the Buckpasser. The noise on
the line would cause a false triggering of the motor, causing it
to run a little and thus the loss of the first 50¢ pulse.
4. Clean relay. A dirty contact can cause continuous motor run
or a locked-up selection system.
5. Check value of 10 ohm resistor (Rock-Ola #43531). If it has
risen even a couple of ohms, a continuous motor run condition
will exist.
6. Make sure all pins and sockets are locked tight in housings,
including relay socket. A loose wire can cause whole
bunches of problems.
7. I repeat, this is only for programmer #51610, (the ones with-
out the bonus setting switch). ADD a 33 ohm½ watt resistor in
series with a .1 MFD @ lO0V capacitor across the relay coil.
You can do it easily at the socket going from the white wire to
the yellow-green wire. This prevents a condition where the
dollar is accepted, the credits appear and then are cleared
before a selection can be made.
This may all sound like a lot of work (it really isn't if you do it
properly the first time), but when you weigh the cost and time
against a second or third service call, this procedure is
worthwhile.
MIDWAY
''GALAXIAN''
'' PAC-MAN''
SUBSTITUTE
+5VDC
POWER
TRANSISTOR
An inexpensive and easy to
find+5VDC power transistor
substitute for the D44VM4
used on Midway's
''Galaxian''
and
"Pac-Man"
video logic boards is
the (Tl) TIP31C.
The TIP31C silicon power
transistor is an NPN type
rated at 3A, lO0V, 40W.