Re: CRT based RPTV Convergence Repairs
Bowing on all sides means the power to STK convergence chips is missing. Replace the two STK chips, blown fuses(or pico fuses) and open resistor if any.
This is not the only possibility. Likely, yes, but you could also have a failure in the convergence generator, its power supply, or corrupt data in the EEPROM. These sets have been known to loose all convergence data sometimes. If the settings are all at 127 this is what has happened. These sets can require a great deal more troubleshooting than others because they tended to NOT have a lot of problems with the output ICs. I have seen problems with supplies, capacitors, diodes and data, along with coolant leaks, but these have been pretty reliable in terms of the normal convergence failures you see on many other sets.
Botttom line is, if you don't have a service manual, the service bulletins, and the experience and equipment to troubleshoot the set, don't be surprised if the common symptom repair help is of little use on this one.
If the convergence data is at defaults (127), you will need to do an EEPROM reset in the option menu and start from scratch on the geometry and convergence.