Star Tech Journal

Rowe BC-25 Coin
Changer Problenis
Erik Wittenzellner
Kemp Enterprises
South Windsor, Connecticut
Nintendo
Playchoice-10 Mod
Dennis C. Dove, Technical Service
Nintendo of America
Redmond, Washington
PROBLEM
SUBJECT
ToeBC-25MCunitwascountingtoomanycoins
into the escrow buckets. Sometimes up to
$16. 75 or more for $1.00 before going out of
order!
Dr. Mario Rom Pcb.
SYMPTOM
It took some time to track down this problem as
I was not sure which system was failing. I knew
the coin sensors were good because the unit
would go out of order if a lamp was covered. Toe
unit would vend when a bill was inserted or a
vend button pushed. The control computer was
tried in a good changer and checked out fine.
What's left?
SOLUTION
Toe power supply board assembly. It turns out
that the emitter-collector of Q201, an MPSA06,
was shorted on this board. I was quite surprised
when I found this and happy I did not condemn
the control computer. I have found a lot of
problems can be traced to this little board, so do
no forget about this one in a problem situation.
To ensure proper operation and to prevent po-
tential IC damage, check the following Short
Land (SL) and Cut Land (CL) locations of the Dr.
Mario Rom PCB before installing onto a
Playchoice Main PCB.
SHORTS
Short Land locations SLl, SL9, SLl0, SL14,
SLl 7 and SL18 should be connected by solder.
Remove solder from all other Short Land loca-
tions.
Curs
Toe trace of Cut Land locations CL5 and CL6
should be cut. All other Cut Land locations
should be connected by a trace or, if previously
cut. connected by solder.
Wells Gardner 7000 Series 25" Vertical
James Beck
Greater Southern Distributing
Atlanta, Georgia
PROBLEM
SOLUTION
Vertical rollover on the top (this is in a Teenage
Mutant Ni.rya n.u-tles) and horizontal lines in the
middle of the screen. Capacitors check good.
Changed the vertical output transistor. Ad-
justed the 50-60 control. Still no luck.
Check D25, it might be open. If that doesn't do
it, try evaluating R80. It might be out of toler-
ance. Replace it if it has a slightly higher value
than specified (even a couple ohms difference).