SHARP 21VR2
Manual de Servicio

21VR2 21VR2

PROTECTOR PERFORMANCE CHECK
No. Adjusting point 1 Beam protector Adjusting procedure/conditions 1. Receive the E-5CH (monoscope pattern) signal. 2. Set the contrast control to maximum. 3. Set the brightness control to maximum. 4. Make a short-circuit between the collector and emitter of Q851, Q852 or Q853 and make sure that the protector is activated and the stand-by mode is called. Waveform and others * Short-circuit any of the Q851, Q852 and Q853. 1

FUNCTION CHECK (VIDEO AND AUDIO)
No. Adjusting point CONTRAST key Adjusting procedure/conditions 1. Receive the E-5CH signal. 2. Select the contrast on the P-MODE screen. 3. The contrast must be changeable with the UP/ DOWN key. 1. Receive the E-12CH signal. 2. Select the colour on the P-MODE screen. 3. The colour must be changeable with the UP/ DOWN key. 1. Receive the E-5CH signal. 2. Select the brightness on the P-MODE screen. 3. The black level must be changeable with the UP/ DOWN key. 1. Receive the NTSC colour bar signal. (A/V) 2. Select the tint on the P-MODE screen. 3. The tint must be changeable toward green with the UP key and toward red with the DOWN key. 1. Press the NOR. key on the P-MODE screen to make sure all the displayed items are at normal settings. See below for the normal settings. » Contrast » Colour » Brightness » Tint » Sharpness : MAX : CENTER : CENTER : CENTER : CENTER * The contrast, colour, brightness, tint and sharpness settings are all normal when these items do not appear on the screen. Waveform and others

2

COLOUR key

2

High-voltage protector

1. Receive the E-5CH (monoscope pattern) signal. 2. Connect the bias box to the cathode (R635 side) of D607. 3. Adjust the bias box voltage to 18 V and make sure that the protector is not activated. 4. Adjust the bias box voltage to 27 V and make sure that the protector is not activated. 1. In checking the performance of other protectors � for example, the one against shorting of smoothing electrolytic capacitor of +B line �, pay attention not to damage or deteriorate any related element.

3

BRIGHTNESS key

3

Other protectors

4

TINT key

5

PIC-NOR. key

10

A/V INPUT AND OUTPUT CHECK
No. Adjusting point 1 Video and audio output check Adjusting procedure/conditions 1. Receive the E-12CH colour bar (100% white colour bar, 400 Hz, 100% modulation audio) signal. 2. Terminate the video output with a 75 ohm impedance. Make sure the output is as specified (1.0 Vp-p ±3 dB). 3. Terminate the audio output with a 10k ohm impedance. Make sure the output is as specified (1.76 Vp-p ±3 dB). Waveform and others 6 SHARPNESS key

1. Receive the E-5CH signal. 2. Select the sharpness on the P-MODE screen. 3. The sharpness must be changeable with the UP/ DOWN key.

7

Channel sign display colour

1. The display colour of all the channel (0-99) signs must be green. Keep the AFT on.

2

Video and audio input check

1. Using the TV/AV key on the remote controller, make sure that the modes change in the order of TV, AV1, AV2 and TV again and that the video and audio outputs are according to the input and output terminals for each mode.