Take a 68k resistor and ground the red cathode, screen should go red with
retrace. If not you have a bad crt. Then trace the signal back from the red
output devcie to the video processor is to determine if indeed you are
getting red video bias and drive from that area. Good schematic and scope
will assist greatly.
wrote in message
ps.com...
model number Q 2770 lack of red on the screen, replaced the crt board,
with one from a working tv, but after finding r 936 open (220 ohms),
picture is still lacking red, & I ca't find any resistors open, or
leaky, or shorted diodes, or drive transistor. What could it be?
Thanks for your time, Robin.