found this stuff relating to the thumping heartbeat power problem but will be a while before I can try any of it: No. The CRT driver ICs are prone to shorting and cause this symptom (I just had one with those very symptoms and the green CRT driver IC was shorted). Disconnecting the CRT board does not clear the short on the board. Often then is a small burn mark on the CRT board under the affected IC (but not always). The IC should be a TDA6111Q. Be sure to note the proper position of the IC as it should face with the letters TOWARD the heat sink!!!! Check the CRT driver ICs on each of the CRT boards. I would disconnect each crt board and hv lead one at a time and try. Have seen several bad tubes on that model. The only other problem I have seen on that set is bad convergence amps, however that doesn't cause shutdown. when turned on Video drive IC (IC1101) on the red CRT module shorted. It looked like bad solder on the B+ was the cause Frequently Used Top Five Repair Parts by symptom code MODEL NUMBER : AV48WP30 - TV SYMPTOM CODE : DEAD TOP FIVE PARTS : 2SC5552-RL 2SC5904-RL QQH0113-002 STR-F6629B/F7 STK392-110 Above from JVC Web site, also I have seen shorted video drive IC's on the crt boards short and cause this symptom. Try unplugging the 200 volt source to the crt boards and see it the set powers up and stays on. There is a B+ relay which supplies 130 Volts to the horizontal output circuit. Is this relay energizing? I takes about five seconds after the power is turned on for it to energize. If a short is detected on the 130 volt line the blue power lamp on the front will do what you describe and the relay will pulse on and off. symptom: Non-functional Digital Input Solution: 1. Power off the unit 2. Disconnect the digital input if it is connected 3. Remove the rear cover 4. On the digital input module, using a shorting pin (PC type) or a jumper, short Pin 1 and Pin 2 of the SB connector 5. Power on the unit 6. Unplug the unit and remove the shorting pin or the jumper 7. Re-attach the unit’s rear cover 8. Power on the unit, and input the digital source

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