Star Tech Journal

19
STAR*TECH JOURNAL/OCTOBER 1982
Power Supply Hardware
KBPC25-02
BR-I
KBPC12-02
BR-2
UA723
5vdc
UA723
12vdc
2N3055 (3)
Series Pass Trans. (Heat Sink Assy. )
2.5K (2)
Voltage Pots (Rl6, R28)
IK (2)
Current Limiting Pots (Rl8, R25)
Voltage Distribution
Voltage
Destination
Board ICs (VCC)
+ 5vdc
Game Board ( audio amp)
+12vdc
Coin Door (2 coin meters)
Coin Door ( 2 lockout coils)
CoinDoor(2 #815 lamps)
As can be seen, the + 12 volts has numerous functions . Tracing this voltage
through the machine may be a little confusing, however, since this same
regulated + I 2 volts is referred to as + I 2.6 volts in the game wiring diagram
(coin door) and +13 volts (game board schematics - audio output section).
There is also a + 13 volt test point marked on the game board itself. Keep in
mind that all these voltages are really the same, each emanating from the same
point (game power supply). Diagram 2 may help demonstrate this.
Power Supply Troubleshooting - Since this power supply has been used on so
many previous games, most of the failures are quite familiar by now. In general,
this is a fairly reliable power supply which is plagued by one constant problem.
The problem is the 25-amp 100-volt bridge (BRI) overheating which results in
bad solder connections, a burnt PCB and/or the bridge itself opening internally.
Taito is attempting to rectify this problem by adding heat sinks to the bridge
rectifier (S*TJ Vol. 4, No. 7) and is using different bridges (BR-251 and
KBPC25-02) to determine which bridge holds up best. The added heat-sink
helps, but probably the only solution, since this bridge normally runs at such
high temperatures, is to mount the bridge separately on its own bracket. Using
heavy enough wire ( 16-gauge or thicker) and attaching the bridge to the side or
bottom of the cabinet on a bracket (which also would act like a large heat sink)
would probably provide enough heat dissipation for the bridge to operate. In this
way, even if the bridge does overheat, at least the power supply printed circuit
board will not be burnt (possibly to an unrepairable state).
Any other type of failure with this power supply are infrequent, and should
really not be too difficult to repair. For the technician working on " Jungle
King", keep in mind that only 2 DC voltages are used and that the system reset
signal is generated on this board. This power supply can provide perfect DC
voltages but still can cause the game to be totally nonfunctional if any failure in
the reset circuitry has occurred.
As mentioned earlier, this is a universal power supply, and has been used on
previous games. However, 2 fuse values have been changed.FI was a 15-amp,
and F2 was a 5-amp. These fuses are now both I 0-amp fuses. Don't be confused
by the silk screening on the power supplies (some power supplies have labels
over top the silk screening indicating proper values) or by the fuse values
marked in the game manual "Component Layout" . These fuses ( as indicated in
"Qix" manual revision I) should be IO amps. This is the value to be used in all
games unless otherwise stated. One final note regarding the power supply is a
small error in the schematic drawing.
Should Be Drawn
Sc~_matic Shows
_J FS ~ -
1 •S
4A
J4-2
•S
.,2 e
The error on the schematic is a minor one but can lead to some confusion.
The original schematic has J2 Pin 7 connected directly to the + 12 volt output
bus and J3 pin 6 isolated. This is the reverse of how they are actually connected
in copper on the power supply. J2 Pin 7 should be drawn as being isolated
( connected only from the junction of R32 and R33 to the emitter of pass trans.).
J3 Pin 6 should be drawn as connected to the+ 12-volt output bus (J4 pins 6, 10,
and 12; J3 pins 10 and 12).
Board Set
The board set for "Jungle King" consists of a stacked 3-board set mounted on
the back door, and a separate filter (anti-static, I/O buffer) board mounted just
above the logic boards. These boards include, from top to bottom, a game PCB,
a video PCB, and a CPU PCB. The three boards are interconnected by way of
four 50-pin ribbon cables. There is also a small "ROM board" mounted directly
on the game board for added external memory.
Game Board - The two principle elements of the game board include the I/O
and sound circuitry. The input section receives all switch closures from the coin
door and control panel. The output circuitry includes the coin counter drivers,
the coin lockout drivers, and all sync and video outputs to the monitor.
The sound circuitry, like all recent video games, has its own separate
microprocessor which can access its own separate 12K of program memory and
IK of scratch-pad RAM. The sound processor dictates control over four
separate A Y-3-8910 sound generators, each one responsible for different game
sounds.
Sound Generator Board Test Point
Audio*
Tune while diving in water
IC 49
PSG3 (out 3)
PSG4 (out 4)
Vine swish
IC 50
PSGI (out I)
Diving, running, falling and catch snd.
IC 51
Background music
IC 63
PSG0 (out 0)
*These sounds were identified using an audio tracer and are only partial listings.
Hardware
Sound processor
Z80A
Program ROMs
2732EPROM(3)
Program RAMs
2114 (2)
Sound generators
AY-3-8910 (4)
Color RAM
93419 (82S09)
X-TAL
6MHZ
Diagram 2
Power Supply
J3 Pin 6 - -
J4 Pin 6
-1
Filter Bd.
Yel. Wire
Yel. Wire
r-V1-6
,
- -V1-6---
Coin Door
(Molex Conn.)
Game Bd.
Yel. Wire
/ .
Yel. Wire
,
Pin 9
,
Pin 12 - - - -
Pin 11 _
1 _ -
Gray Wire
, Pin 9
+12vdc Source----------------------------------------➔
1
2
3
1. J3 pin 6 and J4 pin 6 connected to each other in copper on power
supply.
2. Both input connectors labeled V-1, output connector also labeled
V-1 (*two wires crimped on single output pin). V-1 pin 6 input pins
and V-1 pin 6 output pin all connected to each other in copper on
filter board.
3. Pin 11 and pin 12 connected to each other in copper on game board.
(Pins on "H" connector.)
4. Pin 9 on coin door Molex connector final destination of +12vdc.
4