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SERVICE BULLETIN
Concerning 4500 and 6000 Series English Mark Dart Games
February 3, 1987
WARNING--DISCONNECT ELECTRICAL POWER BEFORE ATTEMPTING SERVICE
Due to an error in printed board circuit layout, there is a
problem which may cause short life with the
triac in both
the 4500 and 6000 series game.
The error causes the current to
drive the lamp to be supplied from the gate of the triac instead
of the normal terminals.
Due to the fact that the device is
considerably oversized,
in normal operation (with the 4500) the
gate would handle the current even though the device was electri-
cally mounted on the printed circuit board upside down.
T h e
failures were caused when the bulb burns out with the filament
falling across itself shorting and drawing a much higher current.
If the device had been on the board correctly, the 120 amp surge
capability of the triac would have most often saved the device
from failing.
What to do:
The fix for the 4500 and 6000 is basically the same.
1 .
2 .
3 .
4 .
5 .
6 .
7 .
8 .
Unplug the game from the wall outlet1
Remove the power supply from the game.
Turning the power supply over,
locate the small printed
circuit board under the chassis.
Remove the board from the chassis by unscrewing three
mounting screws.
The triac is held to the board with one screw and nut.
Remove screw and carefully unsolder the triac from PC
b o a r d .
Reinstall the triac in the same location but on the
opposite side of the board.
You must use an insulator
(fig. 1) since the metal tab of the triac is now being
mounted on the foil side of the board.
Resolder triac
and reinsert screw and nut.
Reinstall PC board into
with three screws being
very careful not to pinch any wires as you are tightening
t h e m .
Place power supply back into cabinet, attach plugs from
wire harnesses,
fasten down with screws, and plug into
wall outlet.
C o n t .
