HV tracking across flexible PCB strips

[tony duell]

[...]

> However, there's a flexible plastic strip running between the CRT face and
> the chassis which carries three lines (it's a storage tube rather than a
> conventional CRT) and I'm still getting periodic arcing across these lines
> which of course upsets the display's operation. As far as I can tell,
> there's no 'sandwich' (and hence glue) involved - it's just a single
> plastic strip with conductive traces drawn onto it.

What does this strip connect to? Is it part of the CRT (or connected to the CRT), does
it connect to a coil around the CRT, or what? 

I am wondering if there is something else leaking or flashing over which is causing
excessive voltage to appear here.

-tony