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DECCA 100 CHASSIS
There appear to be Hanover blinds on this set. They are
most noticeable on yellow and orange areas, but are also
present on cyan and under -saturated blue areas. Lack of interlacing was initially suspected, but there are no problems with a monochrome picture or when the colour is
desaturated. The blinds vary in intensity, and appear to
traverse the screen upwards or downwards. They are
present on all three channels.
It will be necessary to set up the delay line circuit phase
and amplitude controls in the decoder. The amplitude of the
direct signal is set by VR241, while the phasing is set by
L204 and L205. These controls should really be adjusted
using an oscilloscope and a special pattern generator. If the
Hanover bars cannot be eliminated in this way and the continuity of L204 and L205 is intact, the delay line itself is
suspect.