12
NOTES:
1. Outside of the ribbon cables interfacing this board to the CPU, there is only a
single power connector.
2. Pots located on board adjust the horizontal and vertical centering.
3. This board is identical to the video board in 2 board "Donkey Kong" except
that the background PROMs are 2732s in "Donkey Kong Junior", and 2716s
in "Donkey Kong". Early "Donkey Kong Juniors" had modified "Donkey
Kong" video boards. This board had modifications under the PROM sockets to
accommodate the different E-PROMs. Newer games have a new board with the
modifications in copper (no cuts or jumpers required). Other than the different
type of background E-PROMs, the boards are identical (naturally, the image
PROMs (7C, D, E, F) and color PROM (2N) are programmed differently).
TEST POINTS
TPl - Ground
TP2-OBJRQ
These boards have proven to be extremely reliable. Early 4-board "Donkey
Kong" sets had problems with bad sockets, but this problem was rectified on the
two-board sets. Early static problems have also been eliminated with some
minor modifications to the reset circuits. There are some unique parts (DMA
Controller, ECL Translators), but really nothing that should pose any major
problems.
MONITOR
The monitor used in "Donkey Kong Junior" is a Sanyo 19" color rastor-scan
model. Power is provided by an isolation transformer with color and sync
information (generated on the CPU board) connected to the monitor via a 6-pin
ribbon cable. Like older Wells-Gardner models (19K4SOO), the sync is a
composite signal (horizontal and vertical combined) with a separator circuit
incorporated in the monitor. There are two fuses ( see power distribution) as well
as a test switch located on the monitor chassis. This test switch, when toggled,
will cause vertical collapse resulting in a thin horizontal line running the length
of the monitor ( remember, the picture tube is mounted sideways). This test may
be helpful for troubleshooting purposes only. The B+ voltage is adjustable, but
usually no adjustment is necessary (pot is sealed). All monitor adjustments are
easily made with the brightness, horizontal, and vertical pots all conveniently
located and identified on the left side of the monitor (looking from behind with
the back door removed). Keep in mind that in addition to these controls, there
are also horizontal and vertical centering pots located on the video logic board.
No special test equipment is necessary (we use the Crim VG-1 with a
homemade adaptor cable and a Midway isolation transformer). Anyone
familiar with domestic color raster-scans should have no problems repairing
"Donkey Kong Junior" monitors.
CONNECTORS
One of the unique aspects of "Donkey Kong Junior" is the unusually high
number of connectors mounted on the logic boards. Fortunately, these
connectors are all different sizes ( number of pins) and will go on only one way.
While this large number of connectors may seem ridiculous when replacing a
board, it can be helpful in troubleshooting any game failures.
BOARD
CONNECTOR NO. OF PINS FUNCTION
CPU
P 1
SO-pin ribbon logic interface
CPU
P2
SO-pin ribbon logic interface
CPU
P3
3
coin switches
CPU
P4
2
coin counter
CPU
PS
17
control panel switches
CPU
P6
12
not used
CPU
P7
6
video information out
CPU
PS
S
service switch
CPU
P9
9
power in
CPU
PIO
4
audio out
CPU
*Pll
S
not used
CPU
P 12
10
not used
Video
Pl
SO-pin ribbon logic interface
Video
P2
SO-pin ribbon logic interface
Video
P3
10
power in
Video
P4
10
not used
Power Supply
9P (CPU)
9
powerouttoCPUboard
Power Supply
lOP (CLK)
9
powerouttoCPUboard
*There is a space and silkscreening identifying this connector, but no connector
( with male pins) is installed.
NOTES:
1. Connectors identified for upright cabinet.
2. The unused 7-pin connector on power supply (7P SOU) is used in 4-board
"Donkey Kongs" only. (Only 2-board sets are used in "Donkey Kong Junior".)
Most of the connectors snap into place and usually there are no problems
with them. However, since these connectors are different than what anyone else
uses, finding a replacement anywhere other than a Nintendo distributor (if they
have it) is difficult. If a broken connector cannot be readily replaced, then the
wire or wires can be directly soldered until the new connector is located.
STAR*TECH JOURNAL/NOVEMBER 1982
1/0 AND OPTIONS
1/0 - All inputs from the control panel and coin door enter the CPU board.
The control panel switches ( 4-way joystick, jump, I-player and 2-player start
switches) all pass through a resistor capacitor buffering network and then enter
7 4LS240s in locations 2P, 3P, and 4P. There is no slam switch and although the
joystick is not a Wico, it still is very reliable. The entire control panel snaps off
for servicing and can be completely removed by disconnecting the 9P (main
switch harness) connector.
OPTIONS - Option settings for the number of turns, bonus point settings and
various coin/credit combinations are available. The 8-position dip switch to
make these adjustments is located on the CPU Board right below Pl 1. There is
also a setting for cocktail table or an upright cabinet. There are no coin lockout
coils but there is a service switch located on the coin door (between the coin
switches).
SYSTEM AUDIO
The audio layout is a little different than what you are normally accustomed to
seeing. As usual, a separate microprocessor circuit on the CPU board generates
most of the audio. Like many old paddle games, however, the preamplified
audio signal is connected to an audio amplifier board located on the monitor.
After amplification, the signal is fed to an impedance matching transformer and
from the transformer to the speaker.
SYfflM AUDIO
CPU
Board
Audio Amp
(In Monitor)
Imped.
Match.
Trans.
Speaker
Volume Pot
NOTES
1. Audio signal exits CPU board P1 O pins 1 and 2.
2. Audio is preamplified by 01 (C1815) NPN transmitter on CPU board.
3. Audio amplifier board is located on left side of monitor and can be easily removed from monitor for
test or repair.
4. Volume pot (501() is located bottom left side of monitor (next to monitor pots).
5. Impedance matching transformer is located directly below audio amplifier board in monitor.
Resistance on input side approx. 40 ohms. Resistance on outpu1 side approx. 6 ohms.
6. Speaker (4 ohms, 6 watts) located front left of cabinet under control panel.
COCKTAIL TABLES
The cocktail tables come equipped with an 18-inch Sanyo color monitor. The
board set is identical but no metal mounting bracket is used. Screen inversion is
accomplished by the board and is determined by the state of dip switch 8 on the
CPU board (off-table, on-upright). The table wire harness utilizes the 44-pin
edge connector on the CPU board instead of all the individual connectors used
in the upright. There is also a 10-pinjumper connector cable from P12 on the
CPU to P4 on the video board. This is necessary to jump the voltages over to the
video board since only the 44-pin connector on the CPU board is used. (P3, the
voltage input connector for uprights, is not used.)
CONCLUSION
From the service viewpoint, there is no risk involved in purchasing a "Donkey
Kong Junior". Most operators are quite familiar with the system used in
"Donkey Kong" and are well aware of its dependability. This system is almost
identical, and should prove to be even more reliable than "Donkey Kong".
However, some of the same drawbacks (no self-test feature, little documenta-
tion, and a cabinet that is not completely American-proof) still exist. The
problems with the cabinet have been well documented by Todd Erickson in past
issues of Star*Tech Journal in his "On The Service Trail ... " column.
Fortunately, some of these problems that existed in "Donkey Kong" have been
rectified in "Donkey Kong Junior", and should help prevent the various types of
"break-ins" that resulted in free credits.
The service department at Nintendo is very helpful, and most parts (they use
part numbers) can easily be acquired. The only gamble involved with "Donkey
Kong Junior" is the same one involved with the purchase of any remake: Is there
still interest? One thing that does seem apparent, however, is that with games of
this style (cute), nobody does it better than Nintendo.