Star Tech Journal
Issue: 1991-September - Vol 13 Issue 7 - Page 10
(
septenwerJ9QJ
Peter Chou
Power Supply
T'shooting Tips
Adam Spector
Recreational Concepts Inc.
Huntingdon Valley, Pennsylvania
William.s Test 04
Lost Mem.ory
Powers Up In Test
RandyTeny
Alpine Amusement
Connersville, Indiana
SUBJECT
PROBLEM
Here are a few of the more common causes for
Peter Chou power supply failures.
Pinball frequently loses memory or powers up in
Test 04. Batteries and D 1 7 known good.
ti First check the power transistors Q 1 and Q2.
In the circuit it should read about 9 or 10 ohms
between base to emitter. Out of circuit it should
read as a normal transistor.
SOLUTION
Check for voltage at cathode ofD 17 (usually 3.2
- 3.9 vdc) at IC 19 Pin 22 (CMOS Ram).
If missing. repair trace. If not, replace IC 19.
II Next check D8 and D9. They should read
about 100 ohms in the circuit. If you encounter
a low reading, one or both diodes may be bad,
check them out of circuit.
ti Check the main fuse and Rl (1.5 ohm) for good
NOTE
If chip is socketed, check continuity between
chip pins and board (I've had many problems
there). Be sure and discharge yourself first, it's
CMOS.
resistance.
v' Also check the bridge rectifier.
II In a lot of the older Peter Chou supplies (blue
case}, the main filters leak causing power up
problems. Make a visualcheckofC15, Cl6, Cl 7
and Cl9 for leakage.
Electronic Warehouse Corp.
is a good source for the
diodes and transistors.
BOO I 221-0424
The diodes cross to EWC-581.
The transistors are usually
2SC-3039 or EWC-379.
William.s System. II
Settings Response
Tom Bell
GIS Games
San Antonio, Texas
In response to "Williams System II Diagnostics"
on page 20 of your August 1991 issue, after
repairing a switch problem on a Williams pin-
ball, the article says you must use the option of
"Install Factory Settings" to clear the adjust
switch message display by the pinball and then
you will have to reprogram the pinball because
everything gets set to factory settings when you
use the option.
I've found it is a lot easier to just play a game and
activate the repaired switch and the adjust
switch message is cleared. P.S. Think smarter
and not harder.
septenwerJ9QJ
Peter Chou
Power Supply
T'shooting Tips
Adam Spector
Recreational Concepts Inc.
Huntingdon Valley, Pennsylvania
William.s Test 04
Lost Mem.ory
Powers Up In Test
RandyTeny
Alpine Amusement
Connersville, Indiana
SUBJECT
PROBLEM
Here are a few of the more common causes for
Peter Chou power supply failures.
Pinball frequently loses memory or powers up in
Test 04. Batteries and D 1 7 known good.
ti First check the power transistors Q 1 and Q2.
In the circuit it should read about 9 or 10 ohms
between base to emitter. Out of circuit it should
read as a normal transistor.
SOLUTION
Check for voltage at cathode ofD 17 (usually 3.2
- 3.9 vdc) at IC 19 Pin 22 (CMOS Ram).
If missing. repair trace. If not, replace IC 19.
II Next check D8 and D9. They should read
about 100 ohms in the circuit. If you encounter
a low reading, one or both diodes may be bad,
check them out of circuit.
ti Check the main fuse and Rl (1.5 ohm) for good
NOTE
If chip is socketed, check continuity between
chip pins and board (I've had many problems
there). Be sure and discharge yourself first, it's
CMOS.
resistance.
v' Also check the bridge rectifier.
II In a lot of the older Peter Chou supplies (blue
case}, the main filters leak causing power up
problems. Make a visualcheckofC15, Cl6, Cl 7
and Cl9 for leakage.
Electronic Warehouse Corp.
is a good source for the
diodes and transistors.
BOO I 221-0424
The diodes cross to EWC-581.
The transistors are usually
2SC-3039 or EWC-379.
William.s System. II
Settings Response
Tom Bell
GIS Games
San Antonio, Texas
In response to "Williams System II Diagnostics"
on page 20 of your August 1991 issue, after
repairing a switch problem on a Williams pin-
ball, the article says you must use the option of
"Install Factory Settings" to clear the adjust
switch message display by the pinball and then
you will have to reprogram the pinball because
everything gets set to factory settings when you
use the option.
I've found it is a lot easier to just play a game and
activate the repaired switch and the adjust
switch message is cleared. P.S. Think smarter
and not harder.
Future scanning projects are planned by the International Arcade Museum Library (IAML).