Play Meter

1 6 TECHNICAL TOPICS By Randy Fromm of the of the Game Game Doctors Doctors Input In put -+sv +5V ₣8, 9 I~ SW 2 ' 'sw2 O O O O O 16 0 T ST 1 0 U O 18 O 3 2 2 Y z 1 1 R70 15 9 F~ 4 F 3 9312 9312 4 17 330 ADRØ E 7 6 6 5 5 7 Z 14 14 R76 8 10 SPARE SPARE R75 10 3RD 2 3RD 1 2ND2 ENDI ADR5 2 R74 7 R73 27 27 W R71 M R72 285 as S2 SO SII SZ 12 13 11 12 8PLACES ADQ~~+-~~~~~~~~~~~~~~~~~~~ ADRI ADRI AD~2 ADRZ ...~~~~~~~~~~~~~~~~~~~~ ~ ~+--~~~~~~~~~~~~~~~~~~~~~~ 10 9 E AtQ4 ADR4 TRAK SEL 7 START 2 6 13 START 5 N 4 SELF TEST 3 GAS 2 GAS 7 6 5 4 H9 3 9312 2 M -,! IS 5 1 12 -0 M R82 W R83 R81 R80 M 14 SO So SI SI SZ S.? II 12 12 13 13 = 330 7 PLACES R79 ~ R77 M R78 Virtually every every modern modern micromicroVirtually processor-based game system uses uses processor-based game system an input input multiplexer multiplexer scheme scheme to to an couple the the player player control control to to the the couple computer. computer. Because the the majority majority of of input input Because multiplexer failures failures will will show show up up as as multiplexer shorted input input lines, lines, aa VOM VOM can can be be shorted used to to identify identify aa bad bad IC IC on on location. location. used It's aa simple simple process process to to check check the the It's device by by measuring measuring the the resistance resistance device between each each input input and and ground. ground. A A between bad input input will will show show aa considerably considerably bad lower resistance resistance than than any any of of the the other other lower good inputs. inputs . good not uncommon uncommon for for more more than than It's not It's one input input or or device device to to fail fail simultasimultaone neously. Once Once identified, identified, the the bad bad neously. device can can be be replaced replaced and and the the game game device repaired without without pulling pulling the the board board repaired and suffering suffering any ahy additional additional downdownand time. time. Figure one one shows shows aa typical Figure typical input input multiplexer scheme. scheme. In In this this case, case , the the multiplexer device can can be be tested tested by by measuring measuring device the resistance resistance of of the the input input at at the the edge edge the connector. connector. V ,. R69 multiplexer multipl exer failures . Ser vice literature literature Service In the the "Mailbox" "Mailbox" section section oi oi In September's PLAY PLAY METER, METER, Leon Leon September's B. Wiltsey, Wiltsey, Jr. Jr. of of Key Key West, West, Florida Florida B. asked where where he he could could get get some some good good asked literature on on how how to to service service and and literature conduct preventive preventive maintenance maintenance on on conduct pinball machines. machines. Detailed Detailed service service pinball and schematic schematic interpretation interpretation is is availavailand able from from all all of of the the major major pinball pinball able manufacturers (Bally, (Bally, Gottlieb, Gottlieb, and and manufacturers Williams). Williams). These service service manuals manuals can can be be These obtained through through the the distributors distributors or or obtained by writing writing directly directly to to the the factory. factory. by They contain contain aa wealth wealth of of information information They that can can really really help help you you understand understand that and repair repair the the games. games. These These manmanand uals would would be be an an ideal ideal place place for for a a uals serviceman to to start his his service serviceman service literature. literature. Fromm, Game Game Doctors Doctors --Randy Randy Fromm, Atari's Atari's steel pins stee l pins Atari is is now now producing producing steel steel pins pins Atari for its its gearshift gearshift assembly. assembly. These new for These new pins do do not not peen peen at at the the end end like like their their pins aluminum counterparts. counterparts. aluminum At ten ten cents cents apiece, apiece, they they are are aa At worthwhile investment investment for for reducing reducing worthwhile service calls. service Atari's new new parts parts number number for for this this Atari's pin is 73-7C0307SC.. is 73-7C0307SC pin