packard-bell (ugh) A926 some life, deflection, but no HV

[Alex Bird]

Hi,
I'm slowly turning my fear of monitor repair into knowledge and
healthy respect.
I'd appreciate any advice about this fault/model or generally what I
should try next.

I don't know any history of the unit, however it has been used
somewhere _very_ clean, or not used very much.
On connection of power the power supply does a sort of squelchy squeal
for a few seconds. It can then be switched on with the soft power
switch. After a couple of clicks and degauss, I can hear the
deflection coils purring and there is a slight higher pitch whistle.
The sound changes on switching the input signal, and it wakes up from
power-saving when a signal is connected.
There is no static, raster or other signs of HV. The HOT does not
appear to be shorted. The main filter cap has about 307v across it
when on, 320v when 'off' and rapidly discharges when monitor is
unplugged (is that a safety feature or a fault?).
I have resoldered any suspect joints accessable from below, one of
which was a deflection connection, but none looked very bad.
Poking bits with my plastic stick has had no effect.

Any thoughts?
Cheers,
Alex