Date   : Tue, 02 Nov 1999 13:28:28 -0000 
From   : John Simpson <Simpson.J@...>
Subject: Dodgy UHF output from BBC

I have recently obtained an Issue 7 BBC to play with. It works well but the
UHF output seems a bit iffy. Basically, there is a lot of ghosting (even
using a signal booster between the Beeb and the TV). I ran the Watford
Electronics diagnostic disc to see how it displayed blocks of colour and
found the following:

- All colours except for white and yellow: Not bad, a bit fuzzy. 
- White: Lots of horizontal black/white distortion lines on blocks of
colour, lots of ghosting
- Yellow: Horrible! Some yellow is visible but there is a lot of distortion
and lots of white appears.

I thought the TV modulator was probably failing, and tinkered with the wire
connections into it, to no avail. I then tweaked potentiometer VC1, which
seemed to have no obvious effect.

Could it be the TV lead? There doesn't seem to be anything wrong with it.

Any advice gratefully accepted.

john