"Wiebe Cazemier" wrote in message
.home.nl...
On Tuesday 29 April 2008 00:51, Wiebe Cazemier wrote:

On Tuesday 29 April 2008 00:53, Jamie wrote:

why not use a isolation xformer for the heaters?

I also read about those, but didn't investigate. It's basically the same
idea
as winding an extra turn on the flyback, right? Do you simply place it
between the original filament power supply+gnd and filament? How does it
affect image quality, also taking into account the eventual possible
situation that the blue cathode will be in contact with the heater
permanently?

One more question about them: the cathode signal is not DC, so won't
current
from the cathode driver still find it's way to ground through the
transformer?


No, it doesn't work like that, the transformer isolates it. If the primary
was dead shorted, it might have some effect on it, but the video signal is
in the MHz range, the transformer will be around 30KHz.