Classic Mode

Star Tech Journal

Issue: 1984-April - Vol 6 Issue 2

APRIL 1984
~
Problem: Shaky video after game warms up.
The problem is most noticeable in the high-
score screen. Fluttering is seen in the words
"Princess Leia's Rebel Forces" and the scores
sometimes move back and forth.
Solution: Replace the 1 0k.n. resistor at loca-
tion R83 on the video board with a 20k.O..
resistor.
STAR WARS DISPLAY
PROBLEMS
Problem: No filament voltage from the high
voltage (HV) PCB.
Solution: Check for a loose connection on
the lugs that hold the HV transformer to the
PCB.
Problem: The voltage is low on the supply
lines on either tHe Deflection PCB or the HV
Problem: The picture shrinks in from the
negative X and Y sides of the screen.
PCB.
Solution: On some deflection boards, R35
and R12 may have a 15.0.. resistoranda30.0..
resistor in parallel to get 1 o.n.. If these come
loose, then some picture shrinkage may occur.
Solution: There are jumpers on the supply
lines of both boards. The Jumpers are marked
with a "W" on the schematic. They look like
resistors on the board and have a single black
band on them. The jumpers should have no
resistance. However, the brown jumpers may
have created some resistance to them. They
should be replaced with a piece of wire. The
white and tan jumper should have no problems.
24V
Problem: Can any other power transistors be
used on the Deflection board?
Solution: Yes, MJ 15003 NPN replaces
2N3716, and MJ 15004 PNP replaces2N3792.
HVPIN4
Problem: What should the output of the 555
IC on the HV PCB be?
I
Solution: The output at pin 3 on the IC should
be a 20-kHz square wave. This is adjusted
with potentiometer R7.
C10
0.1
R19
&BK
sov
DAGGROUND
Problem: There Is no high voltage. The posi-
tive and negative 24 volts are present.
Solution: Check transistor 03. The problem
may be that the transistor tab (collector) may
not be making good contact with the heat
sink.
ORIGINAL
24V
Problem: The schematics for the HV cutoff
circuit do not match the board assembly.
HV PIN4
Solution: There are three board revisions.
You can tell which one you have from the table
here. The schematics for all three boards are
shown.
I
C10
0.1
sov
R19
68K
DISPLAY REVISION INDICATORS
PCB Revision
R16
R18
Original
First rev.
Second rev.
470.n.
Zener
470.0..
27k.!l.
Missing or 27k.n.
33k.fl.
DAG GROUND
FIRST REVISION
Problem: The schematic for the deflection
board shows CR5 as a 1 N714 diode.
Solution: The schematic number is wrong. It
should be labeled a 1 N751 A zener diode. The
rating of 5.1 volts is correct, however.
Problem: On the HV PCB, the output voltage
of the regulator is good when the pin is lifted,
but there is no voltage when the pin is con-
nected back to the board.
Solution: Check for a bad 0.1 uF glass capa-
citor across the voltage regulator. The
decoupling capacitor may be shorted.
as
2N3904
HVPIN4
R18
33K
I
C10
0.1 SOV
R17
20K
Problem: The 24-volt regulator has failed.
DAG GROUND
Solution: Check for cracking around the
regulator leads on the PCB. Also check for
cracking around the leads of C3 and C4.
SECOND REVISION
APRIL 1984
26
Manufacts continued from page 20
7. Check the IC-pins listed in Table 1 with
the Data Probe and verify that the cor·
responding 1 or 0 LED on the CAT Box is
lit.
8. Set the R/W MODE switch to (OFF) and
repeat steps 5 through 7 using address
5555 in step 5. See Table 1, page 27.
TROUBLESHOOTING THE
DATA LINES
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCB.
2. Connect the Data Probe to the CAT Box.
3. Connect the Data Probe ground clip to a
ground on one of the PCBs under test.
4. Set the CAT Box switches as follows:
a. BYTES
b. PULSE MODE
c. R/W (not)
d. R/W MODE
5. Enter address 0800
1
UNLATCHED
WRITE
(OFF)
with the CAT- Box
keyboard.
6. Press the DATA SET pushbutton.
7. EnterdataAAwlththeCATBoxkeyboard.
8. Setthe R/W (not) MODE switch to PULSE
and then to STATIC.
9. Check the IC-pin listed in Table 2 on page
27 with the Data Probe and verify that the
1 or 0 LED on the CAT Box Is lit.
10. Set the R/W (not) MODE switch to (OFF)
and repeat steps 6 through 9 using data
55 in step 7.
TROUBLESHOOTING THE
WORKING RAM
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCB.
2. Set the CAT Box switches as follows:
a. DBUS SOURCE
ADDR
b. BYTES
1024
c. R/W (not) MODE
(OFF)
d. R/W (not)
WRITE
3. Enteraddress0OOO(MasterPCB)or0010
(Slave PCB) with the CAT Box keyboard.
4. Sett he R/W (not) MODE switch to PULSE
and back to (OFF).
5. Set the R/W (not) switch to READ.
6. Setthe R/W (not) MODE switch to PULSE
and back to (OFF).
7. The Working RAM is a 2K x 8 device. To
test the entire device, set the R/W (not)
switch to WRITE and repeat steps 4
through 6.
8. If the CAT Box reads data that does not
match that entered in step 4, the
COMPARE ERROR LED will light. The
CAT Box ADDRESS/SIGNATURE read-
out will indicate the address location of
the error.
TROUBLESHOOTING THE
COMMUNICATION RAM
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCB.
2. Connect a jumper between the RES and
GND test points.
3. Set the CAT Box switches as follows:
a. DBUS SOURCE
ADDR
b. BYTES
1024
c. R/W (not)
WRITE
4. Enter address 0800 with the CAT Box
keyboard.
5. Sett he R/W (not) MODE switch to PULSE
and back to (OFF).
6. Set the R/W (not) switch to READ.
7. Setthe R/W(not) MODE switch to PULSE
and back to (OFF).
8. The Communication RAM is a 2K x 8
device. To test the entire device, set the
R/W (not) switch to WRITE and repeat
steps 5 through 7.
9: If the CAT Box reads data that does not
match that entered In step 5, the COM·
PARE ERROR LED will light. The CAT Box
ADDRESS/SIGNATURE readout will
Indicate the address location of the error.
TROUBLESHOOTING WITH
CHECKSUMS
NOTE
This procedure can only be done with those
CAT Boxes equipped with a Checksum switch.
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCB.
4. Setthe R/W(not) MODE switch to PULSE
and back to (OFF).
5. Set the R/W (not) switch to READ.
6. Setthe R/W (not) MODE switch to PULSE
and back to (OFF).
7. If the CAT Box reads data that does not
match that entered in step 4, the COM·
PARE ERROR LED will light. Use the
DBUS SOURCE switch to aid in deter·
ining the location of the error.
TROUBLESHOOTING THE
SLAVE DISPLAY RAM
NOTE
The following procedure erases one-half of
the bit map while the other half shows Its data
on the game display. Steps 6 and 9 change the
bit map halves back and forth.
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCB.
2. Set the CAT Box switches as follows:
a. DBUS SOURCE
b.BYTES
C. R/W (not)
DATA
1
WRITE
3. Enter address 1200 with the CAT Box
keyboard.
4. Press the DATA SET pushbutton.
5. Enter data 03 with the CAT Box keyboard.
6. Setthe R/W(not) MODEswitchtoPULSE
and back to (OFF).
7. Press the DATA SET pushbutton.
8. Enter data 02 with the CAT Box keyboard.
4. Enter the address given in Table 3 on
page 27 with the CAT Box keyboard.
5. Setthe R/W(not) MODE switch to PULSE
and then back to (OFF).
9. Setthe R/W(not) MODE switch to PULSE
and back to (OFF).
1 0. The game display should be completely
blank. If so, then repeat steps4 through 6
and again verify that the game display is
completely blank. If anything appears on
the game display, then proceed with step
11.
11. Connect the Signature Analysis probes
as follows:
a. START to the VSYNC test point.
b. STOP to the VSYNC test point.
c. CLOCK to pin 8 of IC 6L.
6. Check the CAT Box ADDRESS/SIGNA•
TURE readout for the appropriate
checksum listed In Table 3.
12. Connect the Data Probe to the CAT Box
DATA connector and all probe ground
leads to a Slave PCB ground.
7. Repeat steps 4 through 6 for each address
listed In Table 3.
13. Set the CAT Box Signature Analyzer as
follows:
2. If applicable, remove the jumper between
the RES and GND test points.
3. Set the CAT Box switches as follows:
a.
b.
c.
d.
BYTES
OBUS SOURCE
R/W(not)_
Checksum Switch
1024
DATA
READ
On
TROUBLESHOOTING THE
MASTER DISPLAY RAM
NOTE
The Playfield RAM is part of the Working RAM.
Refer to Troubleshooting the Working RAM to
test the playfield. Only the Motion Object RAM
is tested in the following procedure.
1. Perform the Preliminary Procedure under
Troubleshooting the Master and Slave
PCa
2. Set the CAT Box switches as follows:
a. DBUS SOURCE
ADDR
b.BYTES
256
c. R/W (not)
WRITE
3. Enter address 3000 with the CAT Box
keyboard.
a. START
Positive (up)
b. STOP
Positive (up)
c. CLOCK
Positive (up)
14. Set the TESTER MODE switch to
SIGNATURE.
15. Press the TESTER PRESET pushbutton.
16. Connect the Data Probe to pin 14 of IC 7 A
17. Verify that the CAT Box ADDRESS/
SIGNATURE readout is 0000. If not, there
is an error associated with IC 7 A.
18. Repeat steps 15 through 17 for each of
the remaining RAMs: locations 78 through
7F, BA through BF, 9A through 9F, and
1 0A through 1 OF.

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