Ak52 Chassis Manual Adjustments Procedure; Preliminary; System Voltage Adjustments; Afc Adjustments - Toshiba 29VH27E Service Manual

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
135V±0.5V
135V±0.5V
135V±0.5V
135V±0.5V

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
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

TYPE OF CRT
PHILIPS A66EAK552X54
PHILIPS A66EAK071X54
VIDEOCOLOR A66ECY13X12
PHILIPS W66ESF002X44
29
st
pin (GND) of the CRT socket.