Sync nor synchronization points illustrate field oscillation frequency offset 50 hz is overmuch, can't be triggered synchronization, then should focus on search field oscillator timing components. wyeservice manual download site
(1) the field frequency potentiometer R407 found image does not change, the image is always up series, estimated potentiometer R407 damage, because the machine has been used for years. wyeservice manual download site
 wyeservice manual download site
(2) remove the R407 found already severe oxidation, active contact way, change the new potentiometer troubleshooting. wyeservice manual download site
(3) if R407 normal, can check R408, C404, and poor IC501 whether to change the value, etc.wyeservice manual download site