Ive searched arround and found a few possibilities (be a while before I can check these out myself)
The amplifiers on the crt boards are listed as knownproblem points (TDA6111Q) that tend to fail allong with some of the resistors near them causing the thump symptom.
other parts whish someone said were listed as likely to cause a dead set include :
2SC5552-RL
2SC5904-RL
QQH0113-002
STR-F6629B/F7
STK392-110
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
