Service Bulletin: SB 86

DATE: January 11, 1996

GAMES: Jack*Bot and Congo sample games manufactured before 12-15-95

SUBJECT: Premature loss of battery voltage on the WPC-95 CPU Board

The CPU boards affected have the bare board part number of 5764-14533-08 (screened on back side of board). The circuit boards should have been modified in house, but in case any were missed, follow the modification procedure below.

* Cut trace on the component side of the PCB as shown in Figure A. Tack solder the cathode of a 1N5817 1.0A diode (D28 on drawing and later board revisions) to U21 pin 2 as shown. Solder a short piece of insulated wire from the anode end of D28 to the feedthrough hole near U12 pin 20 as shown in Figure A.

* Solder a 22K ohm 5% 1/4W resistor (R129 on drawing and later board revisions) to the feedthrough holes in the PCB near U18 as shown in Figure B.

* Verify that R91 is a 22M ohm 5% 1/4W resistor.

Thank you,
WMS GAMES Parts & Service INC.