V50000007 datasheet(18/63 Pages) TOSHIBA

18 / 63 page

AK41 CHASSIS MANUAL ADJUSTMENTS PROCEDURE

A) 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.

B) SYSTEM VOLTAGE ADJUSTMENT

Inputs

- AC power (220V 50 Hz).

- PAL B/G test pattern via RF

(PAL I test pattern for PAL I TVs, 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 analogue controls (volume, bass, treble, brightness, contrast, colour) to minimum settings.

- Adjust VR127 according to the following different types of CRTs

SYSTEM VOLTAGE

TYPE OF CRT

135V±0.5V

PHILIPSA66EAK552X54

135V±0.5V

PHILIPSA66EAK071X54

135V±0.5V

VIDEOCOLORA66ECY13X12

135V±0.5V

PHILIPS W66ESF002X44

C) AFC ADJUSTMENT

Inputs

- AC power.

- 38.9 MHz test pattern for PAL B/G, PAL-SECAM B/G or 39.5 MHz test pattern for PAL I model

(90dBmV) to Z403 SAW filter input terminals 1 and 2.

Outputs

- Digital Voltmeter to AFC point (pin22 of IC401)

Display

- AFC Voltage.

Action

- Adjust VL401 for 2.5±0.1 Volts. TV should automatically tune to a station when

search tuning is activated.

D) FOCUS ADJUSTMENT

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 potentiometer (the upper pot on the rear side of the FBT transformer) for optimum

focusing.drive.

E) SCREEN ADJUSTMENT

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 1st 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.

F) IF ADJUSTMENT FOR L MODE

Inputs

- AC power.

- 38.9 MHz test pattern for PAL B/G, PAL-SECAM B/G or 39.5 MHz test pattern for PAL I model.

(90dBmV) to Z403 SAW filter input terminals 1 and 2.

Outputs

- Digital Voltmeter to AFC point. (pin22 of IC401)

- Digital Voltmeter to AFC_L point. (pin14 of IC401)

Display

- AFC Voltage.

Action

- Firstly adjust VL401 for 2.5 ± 0.1 Volts. TV should automatically tune to a station.

when search tuning is activated.

- Adjust VR401 for 2.5±0.1 Volts at the AFC_L point.

V50000007 Datasheet(PDF) 18 Page - Toshiba Semiconductor

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