Panasonic TX28PB50 Euro 7

[Turnip]

Hi folks,
Have one of these where at switch on, PS pulses for perhaps 10 seconds then cuts. Thought to check LOP collector which shows little initial voltage, but resistance wise (Avo 8 of course), it's 12 Ohms one way and 100 Ohms the other. Suspect 100 Ohms is too high for a PS secondary diode short - any thoughts ?  - Chris.