Toshiba 29VH27D, Service Manual

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15.AK52 CHASSIS MANUAL ADJUSTMENTS PROCEDURE
15.1.PRELIMINARY
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.
15.2.SYSTEM VOLTAGE ADJUSTMENTS
Inputs AC power (220V 50Hz)
PAL B/G test pattern via RF
(PAL I test pattern for PAL I TV’s, SECAM D/K pattern, SECAM L/L’/K’ TVs.)
Outputs Digital voltmeter to anode of D110.
Display System voltage
Action Apply power. Check that the stand-by Led lights.
Select TV mode and tune to the applied test pattern via local test keyboard.
Chassis should start normally.
Adjust all analog controls (volume, bass, treble, brightness, contrast, colour) to minimum
settings.
Adjust VR127 according to the following different type of CRTs.
SYSTEM VOLTAGE TYPE OF CRT
135V±0.5V PHILIPS A66EAK552X54
135V±0.5V PHILIPS A66EAK071X54
135V±0.5V VIDEOCOLOR A66ECY13X12
135V±0.5V PHILIPS W66ESF002X44
15.3.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.
15.4.FOCUS ADJUSTMENTS
Inputs AC power
PAL B/G test pattern via RF input.
Outputs Picture tube drive.
Display Picture
Action Select TV mode and tune to the signal.
Adjust focus potantiometer (the upper pot on the rear side of the FBT transformer) for
optimum focusing drive.
15.5.SCREEN ADJUSTMENTS
Inputs AC power
PAL B/G Colour Bar test pattern via RF
Outputs 1/100 Oscilloscope probe to RGB cathodes on CRT baseboard.
NOTE: Ground pin of probe will be connected to 1
st
pin (GND) of the CRT socket.
Display RGB ratio
Action Select PAL B/G Colour bar pattern using the local test keyboard and the user remote
control unit.
Adjust all control functions (brightness, colour and contrast) to minimum settings.
Measure the most sensitive cathode
Adjust the screen potentiometer (lower pot on the rear side of FBT transformer) until
cathode voltage becomes 150V.
15.6.IF ADJUSTMENT FOR L’ MODE
AFC is automatically adjusted from software , when f (IF) is selected 33.9MHz for
positive modulation (SECAM L’) from the service menu.
16.AK52 CHASSIS PRODUCTION SERVICE MODE ADJUSTMENTS