We have a Hitachi Plasma screen - model 42PD6A10 - new in December
2007.

Symptoms:
Recently the screen colour on the whole screen would intermittantly
have incorrect colours. White would stay white, black would stay
black but most midrange colours became primary and incorrect! This
effect would be intermittant during an evening of viewing, sometimes
being OK for 30mins and then being faulty for an hour.
For example, the peoples faces would all turn blue or green, a scale
from white through grey to black would show white light green the
light pink then black. The problem was consistant - one shade of blue
always became a particular shade of brown.

To be clear this wasn't: a very high colour saturation, a primary
colour not working, primary colours "swapped". It wasn't effected by
the brightness control on the TV, although the incorrect colours could
be slid along the colour scale using the contrast adjustment.

The error occurs on all channels and also on the "blue screen" no
signal screen

Cause:
Since Hitachi were not very helpful at supporting this screen, we took
the back and several circuit boards off. You will require torx and
cross head screwdrivers. The fault was found to be POOR DESIGN AND A
FACTORY BODGE.

Solution:
Near the centre lower on the reverse of the screen,are two circuit
boards stacked over eachother with a sheet of metal in between.
Connecting to the lower board is a 24 (?) way connector with two
packages of cable in black tubes. This female connector has no
latching into its male half which is mounted on the lower board. The
lower board is a small board which connects to the XSUS board and the
YSUS board and the lower edge connectors with a white ribon cable.

Due to the lack of a correct latching pair design, and the stiff set
of cables into the connector, any vibration or thermal effects will
cause the connector to ease out of place. Hitachi have attempted to
fix this by using tape - yes black gaffer tape - to hold the cables at
two points onto the frame and onto the circuit board.

By tidying this cable routing and taping more effectively we have
cured the problem.


PS. Please also send followups to my email address, since I'm unlikley
to check this group frequently.