International Arcade Museum Library

***** DEVELOPMENT & TESTING SITE (development) *****

Star Tech Journal

Issue: 1990-May - Vol 12 Issue 3 - Page 7

PDF File Only

Reduce Picture Width
on Wells Gardner 7601
Frank 'ibe Crank" Seninsky
Alpha-Omega Amusements & Sales
Edison, New Jersey
SYMPTOM
The picture on your newly converted game is
too wide and the monitor is a Wells Gardner
7601. Adjusting the horizontal width coil
shrinks the picture, but not enough.
FORMULA
The formula for total capacitance of two
capacitors in series is (CT)=Cl x C2/
(Cl+C2). Ifyoudon'tfeellikedoingthemath,
just use your capacitance tester.
TEST
The next natural step is to measure the B+
voltage. B+ should be at 123 volts on this
monitor. It can be measured at Pin 4 of the
voltage regular (IC4).
The final step is to fine tune the picture by
readjusting the horizontal width coil.
CHECK
If your B+ is higher than normal, but not
high enough to activate the x-ray protection
circuit, you would have a similar symptom.
Our B+ checked OK. ..
CURE
Reducing the value of capacitance of C37 on
the monitor easily solves the problem. Our
symptom was originally encountered when a
Double Dragon II was converted to an MVP.
Ramon, (our senior technician), found out
that by increasing the value of C37, the
picture got wider; by decreasing the value of
C37, the picture shrunk.
VALUE SELECTION
In this case we ended up connecting a 0.22
MFD capacitor in series with the existing
C37 which has a value of 0.15 MFD. This
gave an equivalent value of approximately
0.09 MFD.
By the way, our MVP is doing great and we
sold the Double Dragon II PCB and Header.
Hey There
Mr. Jukebox Operator!
Are you frustrated at the high cost of a new CD
jukebox for that location that just won't justify it?
Well, don't junk those old 45 phonos!
Coming next month,
a new CD jukebox conversion kit ...
For more information, call the
CD JUKEBOX KIT CO.
at 901/364-5140 or
fax 901/364-3303.

Future scanning projects are planned by the International Arcade Museum Library (IAML).