Star Tech Journal

6
STAR*TECH JOURNAL/JULY 1983
WELLS-GARDNER
COLOR X-Y HIGH VOLTAGE SUPPLY
By Daniel Zavaro, San Francisco Music & Games, San Francisco, CA
I recently spent several ·hours diagnosing a problem with a Wells-Gardner color X-
y high voltage power supply. Transistors Q901 and Q902, and resistors R903,
R901 and R907 were burned.
After replacing the bad components, Q901 and Q902 became very hot and
burned out in less than a minute. The defective component turned out to be C905, a
33mfd/150vcap. When measured out of circuit, this capacitor had deteriorated
down to approximately 1.4mfd! The solution is to replace C905 with a 50mf/
200v cap of good quality. (I used a Mallory brand electrolytic.)
I have experienced this particular problem twice in the last month; upgrading this
cap has solved the problem both times.
C903
H.V. P CB
P 3 16
.015
R902
0.27
J/2W
ZT. 8 V
R9 0 1
2.2
2W
C90 1
100MF
35V
26.:JV
+
, .•
R903
112W
R912
10
1/2W
26. 4V
R905
060
1/2W
R915
1K
C904
O. IMF
6.81<, 1/2W
Z090I
R908
•·
13V
"
-12 . IV
- 18. f V
R909
IOOK
R9 11
6 ,81(
B+
VID EO B +
R928
56 K
R913
560
5W
1W
-:;:-
R927
150, 1/Z W
R9 17
3. 3, 1/2W
-12. BV
R914
150
l/2 W
R916
3. 3K
-l9. 5 V
2
IC 9 0 I
NE55 5P
R9 21
2.21(
- 2 4.4V
I I
§
R923
3.31(
31-"N>r--t---+-"""'-tt..
- Z OV
Rgz 4
-25V
I
I
560
I
PACE'S
PULSE HEAT POWER SOURCE
Pace's Model PR-10 Pulse Heat Power Source
provides high-duty cycle temperature control
for pulse-type heating.
The PR-10 provides power source for one or
more of four different function tools with integral
power cords for soldering, desoldering, lap
reflow soldering, wire stripping, conformal coat-
ing removal, auxiliary heating, conductive
soldering, repairing broken circuit runs and
unclinching leads.
Pace's PR-10 Power Source includes a foot • 0
switch, 3-wire power cord and ground terminal.
Supporting function tools are available
including Pulse-Heat Thermal Wire Stripper
(Model TS-20-02), a lightweight easy-to-use tool for damage-free removal of wire
insulation, including Teflon; Pulse-Heat Resistance Tweezer (Model TW-20-02)
permitting heating for soldering and desoldering closely spaced pins, terminals and
lugs; Pulse-Heat Conductive Heating Tweezers (Model CT-20-02) for rapid, safe
soldering and desoldering of component leads where resistance heating could cause
component damage; and Pulse-Heat Probe (Model TP-20-02) with pencil-like
design and a variety of quick-connect tips for conformal coating removal, lap reflow
soldering and lead unclinching.
Pace's PR-10 and all related function tools are available from Pace representatives
worldwide. More information may be obtained by contacting Beth Amelio, Pace
Incorporated, 9893 Brewers Court, Laurel, MD 20707. (301) 490-9860.
62
544v
FOCIJS
5.7kv