z wrote:
ian field wrote:

One possible cause is high value start up resistors in the PSU going very
high, this can mean the PSU doesn't start immediately but can be got
going
by a random mains spike.

Here is another clue, sometimes it will startup when I press the
tv button (which switches between the normal aerial channels
and the sky digibix scrat connection, seems like your spike
theory is gaining ground...

Its been established in the flow of posts so far that your PSU is almost
certainly starting normally and the line O/P is very probably doing so as
well, it seems increasingly likely that the auto-greyscale circuit is
detecting an excessively worn CRT and shutting down the cathode drives. On
some sets an incorrectly set first anode can also confuse the g/s circuit.

Why would it be doing that? What possible consumer benefit could be
obtained by greyscale shut down as you describe? Are you seriously
saying that the people at Panasonic will deliberately install a circuit
that
shuts down the tv. I have never heard of such a thing, they could be
sued for that. Are you really sure about that???

oh, I see all the "experts" are joining in...
so if as the original replyer suggested the
grayscale circuit detected a bad crt than
the common sense thing to do would be
to make the tv stop working now rather
than give the poor customer a few more
month of pleasure. Sure, I believe you...