Models like the TC-21RX20C often share identical schematics with regional siblings (e.g., TC-21RX20, TC-21RX20P, or TC-21RX20M).
I can guide you through the exact schematic paths and testing steps to isolate the issue. Share public link panasonic tc-21rx20c circuit diagram pdf
The vertical output IC (commonly an AN1552x or LA78040 series chip). It is a frequent failure point in older Panasonic TVs. System Controller / Chroma IC (The "Jungle" IC) Models like the TC-21RX20C often share identical schematics
: 17 systems covering VHF (2-13), UHF (14-69), and CATV (1-125) Service Manual Contents and CATV (1-125) Service Manual Contents