Play Meter

6 By Randy Fromm • Troubleshooting Tro ubleshooting Motorola monitors Motorola encounter at some time or another. PROBLEM-BlowsFuses Fuses PROBLEM-Blows Remove Q9 Q9 (horizontal output Remove (horizontal output transistor) and test with a V.O.M. or transistor) and test with a V.O.M. or othersuitable suitable transistor transistor tester. tester. See See other Technical Topics July, 1977 for Technical Topics with July,your 1977 for transistor testing V.O.M. transistor testing with replace your V.O.M. Q9 tests tests bad, bad, and IfIf Q9 replace itit and retest the monitor. If Q9 tests good or retest the monitor. If Q9 tests good or the monitor still blows the fuse, the monitor blows fuse, remove the still + 73 volt theregulator remove the +73 volt regulator transistor (A8W) (A8W) and andtest test asas above. above. transistor If the regulator transistor tests bad, If the regulator transistor tests replace it and retest the monitor.bad, If it replace it and the monitor. If it tests good orretest the monitor still blows tests good the the monitor still blows the fuse, fuse, or test power supply the test the power supply diodes. One or more of the four diodes. One or more of the four diodes in the bridge may be shorted. diodes thediodes bridgemay maybebetested shorted. Again,inthe with Again, the diodes may be tested with your V.O.M. yourIf V.O.M. the diodes diodes test test bad, bad, replace replace If the them and retest the monitor. the them and retest the monitor. IfIfthe diodes test good or the monitor still diodes testfuse, goodisolate or thethe monitor still blowsthe the transformblows fuse, isolate the transformer secondary leads from the power er secondary leads from the power HOR IZ HORIZ DEFLECTION :10RIZ HORIZ BlANKING DEFLECTION YOKE YOKE 1 IC24 J150MF K 9 DAMP[R DAMPER DI LDIDID DID -O + +150V C29 BOOT 1.56 +550V 310 101 13 317ZIN 30 RECT. 1V 73V 05 33 WIDTH B+ T1 470 [1200V 3 09 HOR OUTPUT A6Z D4 D4 H. V. RECT H.V. RECT 24 11/028' 1.01 PULSE C31 ) 220 R49 150 HORIZ C42 CRT CRT 2ND ANODE 2ND ANODE - D2 D2 DlK 01K PULSE LIM PULSE LIM 227 288 R68 150 1W R46 33K BLANKING C2711MF Learningtoto service service monitors monitorsisis aa Learning good way to get started with solid good way toThe get Motorola started with solidis state repair. monitor state repair. The Motorola monitor is simply laid out and easy to undersimply laid outis and easy to under-of stand. There also an abundance stand. There is also an abundance of excellent technical technical material material that that isis excellent available free of charge from Moavailable torola. free of charge from Motorola. The most comprehensive is the The most comprehensive the "Solid StateTechnical TechnicalRepair RepairisManMan"Solid State ual." This manual covers each ual." This manual covers each section of the monitor in great detail, section of the monitor in greatofdetail, and explains the function each and explains the function of each component in the section. The component the section. Motorola in part number The number isis Motorola part 68P65130A74-l. You can obtain 68P65130A74-1. You can obtain aa copy by writing or telephoning copy by writing or telephoning Motorola Data Products, Products, 455 E.E. Motorola Data 455 North Ave., Carol Stream, Illinois Illinois North Ave., Carol Stream, 60187. Tel. 312/ 690-1400. 60187. Tel. 312/690-1400. One of the things that makes the One of monitor the things that theis Motorola easymakes to repair Motorola monitor sosoeasy to repair is the fact that there are some half the fact that there are some half dozen common failures that are dozen common that Once are incredibly easy tofailures diagnose. incredibly easy to diagnose. Once you see each of these failures, you see each of theseis failures, repairing the monitor often a repairing the monitor is often a matter of popping in a new transistor matter of popping in a some new transistor or two. Here are easy to ordiagnose two. Here failuresarethatsome you'reeasy sureto diagnose failures thattime you're sure toto encounter at some or another. R43 1.5K3W R44 4.7 1 TECHNICAL TOPICS 2 6 230 +73V +73V +73V B+0+ +150V Complete Horizontal Output Circuit Complete Horizontal Output Circuit FigureOne One Figure C43D IZOMF T2 T2 H.V . H.V. TRANS TRANS