Star Tech Journal

June 1987 (5)
STAR*TECH Journal
VA+
Exidy TOP SECRET Power Mod
By Exidy Customer Service
Fremont, california
IM741 Power Re-Direction fvk>d.
Following is our specifications for
CROSSBCM--type audio board modifications.
'Ibis modification will reduce comµ:ment
stresses and provide for better
reliability.
'Ibis change should be made on '!OP SOCRET
games purchased before March 1, 1987. ('!OP
SOCREI' games sold after this date have
already been modified.)
-
VA-
It is also being recommended for CROOSBCW,
CHEYENNE, ~CKSHOT, CA'ICH-22, CHIU..ER,
and CLAY PIGEON. Al though these GUN games
will function fine without the rood, it is
recornmended as a preventative rreasure and
will increase long term reliability.
TOCHNICAL DFSCRIPI'ION:
'lbe supply voltage to the LM741 is being
redirected from +18V/-18V to +12V/-12V,
also a current limiting resistor has been
added. (See circuit diagrams.)
E:'1.1S1"1N6
Williams Pins Power Supply
Low+SVdc
Vflt
+33,,_f
~
r
Sam Cross
Godwin Distributing Co.
North Little Rock, Arkansas
PROBLEM:
ool
'-'..f
VA-
By
3Jf.tf
A
PRCX:EDURE:
•
A 1k ohm, 1/ 4 watt resistor is added to
the base circuit of Qll and Ql2. Also, the
supply voltage is switched from +/-18v to
+/- 12v.
Low
+SVOC
POSSIBLE CAUSE: 'lbe reason for this
service note is that this component may be
overlooked in trying to find the cause.
CB, a 47 microfarad at SOVOC capacitor may
have opened up.
I encountered this problem shortly after I
was told about it at the A01E show in New
Orleans this past March. I have
encountered this cap as being the problem
only once before, but other technicians
seem to have encountered this cap as being
resµ:>nsible for low +SVOC several times
in the past.