"Clint Sharp" wrote in message
...
In message , ian field
writes
The fault is either convergence or colour purity,
It's not convergence.
More likely is the static convergence and purity rings on the CRT neck
between the scan coils and the CRT base board, these rings are usually
moulded plastic with a magnetic filler and are usually mounted on a
The fault is almost definitely not related to the purity/convergence
rings as it's intermittent/changing, the crackling noise gives it away as
a problem with the degauss circuit, either a dry joint on one leg of the
posistor or coil connector, a faulty posistor or degauss coil. I'd replace
the posistor first and re-solder all associated connections.

If you can get hold of a service manual and borrow a test pattern
generator
the realignment procedure is really quite straightforward matter of
following the steps described in the manual..
If you mess about with the rings to try and fix a fault, you'll definitely
need a test pattern generator and a lot of patience.



--
Clint Sharp

That's certainly possible, and dry joints around the degauss posistor (or
its relay if it has one) are not at all unlikely now so many manufacturers
are using lead-free solder - it seems to almost fall apart after only a
couple of years!!!