Canon LV-7105 Service Manual - Page 85

Part 4: Troubleshooting 1.3 No Picture 1) AV board 1. Check that the Vcc-voltages(+5V, -5V) are applied to AV circuits. Pins 47-50 of K10A, Pins 47-54 of K10B 5V Pins 39-42 of K10B 5V Check IC1001, IC1002 and IC1021. 2. Check that the following input signals are observed correctly. SIGNAL V-Sync H-Sync B G R Video S-C S-Y K10A-pin No. K50A-pin No. 17-18 17-18 15-16 15-16 11-12 11-12 9-10 9-10 7-8 7-8 33-34 33-34 29-30 29-30 25-26 25-26 2) Main board 1. Check the signals at following test points. • Video signal at TP208, TP218 • V-sync signal at TP7224 • H-sync signal at TP7223 2. Check that the PC/AV switching signal is correct. Pin 16 of IC5201 AV: H, PC: L Pin 5 of IC5282 AV: H, PC: L 3. Check that the RGB signals are observed at following test points. TP211, TP221R, TP2211R R-signal TP212, TP221G, TP2221G G-signal TP213, TP221B, TP2231B B-signal 4. Check that the signals are observed at following test points. TPDHS, TP3322 V-Sync, TPDVS, TP3321 H-Sync 5. Check that the RGB drive signals are observed at fllowing test point. TP501 R-signal TP531 G-signal TP561 B-signal 6. Check that the S/H signals are observed at following test points. TP1501, TP501R, TP502R R-signal TP1531, TP503G, TP504G G-signal TP1561, TP505B, TP506B B-signal 7. Check that the PSIG signals are observed at test points TP1401 and TP1451. 4-7