Star Tech Journal

Issue: 1981-February - Vol 2 Issue 12

Sl;q~TECH _ _ _ _ _ _ __ _ _ g
Seeburg
Service
Information
SEEBURG IS BACK IN THE MUSIC BUSINESS WITH THE NEW
"PHOENIX" AT STERN ELECTRONICS, INC., 1725 WEST
DIVERSEY PARKWAY, CHICAGO, ILLINOIS 60614.
STERN ELECTRONICS IS NOW IN A POSITION TO SERVICE
YOUR DISTRIBUTOR WITH PARTS AND SERVICE GOING BACK
TO 1975. THIS INCLUDES THE VOGUE 11, THE ENTERTAINER,
THE FURNITURE CONSOLE, THE DISCO, AND SEEBURG'S
NEWEST PHONOGRAPH, THE "PHOENIX".
STERN ELECTRONICS IS CURRENTLY SERVICING
TRANSMITTERS, RECEIVERS AND MCU'S. PLEASE CONTACT
YOUR SEEBURG DISTRIBUTOR FOR MORE INFORMATION.
STERN ELECTRONICS WILL SHORTLY BE INCLUDING WITH
EVERY NEW "PHOENIX" PHONOGRAPH A REQUEST CARD FOR
FREE ADDITIONAL SCHEMATICS.
STERN ELECTRONICS IS PROVIDING A TOLL FREE WATTS
LINE NUMBER, 800-621-6424, FOR YOU TO USE TO GET
SERVICE INFORMATION. PLEASE ASK FOR GENE ROELLE OR
LOU RUDOLPH.
Midway "Space Encounters" Strobe Unit Modifications
SUBJECT:
Strobe unit PC A084-91359-
B645, Serial No. 101 to 3700.
MODIFICATION:
1. Change resistor R3 and RS
to one of the following
values:
1. 300 ohms, 20 watts.
10%.
2. 31 0 ohms, 20 watts.
10%.
2. Capacitor C-2 and C-3
should be 22MF., 250 V.
MODIFICATION:
Additional modification for
safer strobe unit operation.
See Figure 1 for adding fuse.
1. Cut blue wire, pin 3.
2. Add .187 Amp fuse and
holder.
FIGURE 1
PART ND. 0017-00003-0375
BLU.
~ W I R E NUT.
PART ND. 0017-00021-0088
~
'
y ·G . - - - - - -
1
.117 APIP.
...
~~,,.-
STROBE & LIGHT BOARD
P.C. AD84-91359-B845
NOTE: The fuse holder and
wire nut can be
ordered from Midway's
parts department.
l
~
IT]
Midway "Space Zap" Test Equipment
SUBJECT:
Card Rack System Test Equipment
To aid board repair the following test cards are available.
1 .
A Ram Test card to locate a bad Ram. A082-91516-A000.
2.
A Card Rack Test Card which is used with the Ram Test
Card and will also test the pattern card. A082-91517-A000.
3. test cards through your distributor from Midway's
Order
Parts Department.
DJ;
lO _ _ _ _ _ _ _ _ _ _ S~R~ECH
Midway "Pac-Man" Reset CKT
FIGURE 1
7.5
voe
+5V
10MFO ~
25V ;;-.. CID
1K
R28
10K
POR
01
(TO COIN
COUNTER
CIRCUIT)
~
FIGURE 2
SW11
- -
- -
- -
- -
2N3391A
7.5
1 I
AC
IN
p
+5V
1K
V BLANK
7 EP
10
ET
2 CK
3
A
4
B
5 6
C 0
74161
BC
ca
10,000
IOV
10,000
IOV
9
TC
CLR
15
RESET
(TO MICRO-
PROCESSOR)
Ul;
turning "on" the NPN
transistor. During this time,
the collector of 01 is "low",
presenting an active ·POR
(power on reset) to the coin
counter circuit (prevents false
counts during power up) and a
load (Ld) signal to IC 9C
(7 4161) holding the
microprocessor in a reset
condition. After a period of
time (to allow all voltages to
stabilize), C1 O becomes fully
charged and acts as an open
stopping all current flow to the
base of 01, turning it "off" and
releasing both reset signals.
Loss of Displays, 4 76-484 Rock-Ola
On some keyboard/display
boards, the use of copper board
edges instead of nickle plate
has caused a corrosion
condition that leads to
intermittent displays of
"Credit" and "Record Now
Playing."
7
LO
WOR
Symptom:
Logic PCB is locked up
(constantly resetting) and
WDR signal is present (watch
dog reset).
Probable Solution:
C7 or CB (10,000 MFD/1 OV
capacitor) is open.
Theory ( Figure 1):
When power is first applied,
C1 O (1 OMFD/25V) charges to
7.5VDC through R28 and R29.
Resultant current flow
produces a positive voltage
drop at the base of 01,
voe
During normal operation, WDR
occurs to clear the counter
(9C) before it reaches its
terminal count (TC) keeping
Reset inactive.
However, if sufficient ripple
(AC) voltage is present (Fig. 2)
in the 7.5VDC, C10 will charge
and discharge accordingly.
This action will cause 01 to
switch on and off,
consequently resetting the
processing and preventing the
system from fully powering up.
by Chuck Maier
Cleaning the connector on the
board and applying a light
coat of vaseline will prevent
additional service calls.

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