Toshiba 28YT56, Service Manual

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3 AK49 CHASSIS MANUAL ADJUSTMENTS PROCEDURE
Before starting with the alignment procedure, make sure that all the potentiometers on the
chassis and also screen and focus pots are in the medium position.
3.1. SMPS B+ ADJUSTMENT
Prior to first run of TV chasis , FBT screen and focus potentiometers should be set to middle
positions then B+ voltage is measured. If this value is different from the list below ;VR800 is adjusted
to specified value below.
SYSTEM VOLTAGE TYPE OF CRT
145 V±0.5V 32” 16:9 RF Panasonic W76EKW10X21
145 V±0.5V 28” 16:9 RF Thompson THO021X131
3.2.AFC ADJUSTMENTS
AFC is automatically adjusted from software, when f (IF) is selected 38.9MHz for negative
modulation and 33.9MHz for positive modulation from the service menu.
3.3.
FOCUS ADJUSTMENTS
TV is tuned to the signal. Then focus potantiometer (the upper pot on the rear side of
the FBT transformer) is adjusted for optimum focusing drive. For double focus tubes,there
are two focus potentiometer; each of them should be adjusted for optimum focus on the
screen