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REMOVING THE COVER 

1.

Position the display as shown in the
figure; put a cloth on the table under the
unit so as not to scratch the CRT glass
screen. Remove the 4 cover securing
screws V1, V2, V3 and V4. 

2.

Take the cover off; take care not to
d a mag e   th e   ca b l e s  o r  bo ard
components. 

DISCHARGING THE HIGH VOLTAGE

3.

Before removing any board, you must
first discharge the high voltages (25 KV
CRT anode voltage). To discharge the
C R T  a n o de ,  u se   a  s cr ew d ri ve r,
connecting it with a wire conductor to the
monitor chassis ground. Put the point of
the screwdriver under the rubber suction
cap of the anode until it touches the two
contacts of the CRT anode. Hold the
screwdriver in contact with the anode for
a few seconds until the high voltage is
fully discharged. 

V1

V2 

V3

V4

Fig. 20-1  Removal Screws Securing the Video

Cover

Fig. 20-2  Discharching the High Voltage

Video Unit - Pocket Service Guide

20-2

14" COLOUR DISPLAY UNIT - CDU 1435SE/GS11

Summary of Contents for CDU 1435SE/GS11

Page 1: ...35SE GS11 220 V Mains frequency 50 3 Hz 60 3 Hz Degauss On powering up Horizontal Synchronism Frequency 31 5 35 2 35 5 KHz Polarity Negative or positive Level TTL Pull in range more than 250 Hz Hold in range more than 350 Hz Retrace period 5 0 µs max Vertical Synchronism Frequency 56 60 70 87 Interlaced Hz Polarity Negative or positive Level TTL Pull in range 50 87 Hz Hold in range 50 87 Hz Retrac...

Page 2: ...e high voltages 25 KV CRT anode voltage To discharge the CRT anode use a screwdriver connecting it with a wire conductor to the monitor chassis ground Put the point of the screwdriver under the rubber suction cap of the anode until it touches the two contacts of the CRT anode Hold the screwdriver in contact with the anode for a few seconds until the high voltage is fully discharged V1 V2 V3 V4 Fig...

Page 3: ...sconnect the video amplifier board from CRT Disconnect connector B interfacing the main board connector C connected to the video ground 8 Disconnect desolder connectors D interfacing the video signal cable 9 Raise the grid of the G3 focus grid input at the CRT connector on the video board Desolder the connection 10 Disconnect the G2 grid cable 11 The video board is now free of all connection A C B...

Page 4: ...e upside down and draw the two catches of the anode contact closer together 14 Lift off the anode suction cap 15 Disconnect connectors A unscrew the screws and raise the slots that fixing the main board at the support 16 Press catches and raise the board from side A 17 Disconnect deflection yoke D and potentiometers P connectors than press catch B and remove board A Fig 20 5 Removing the main boar...

Page 5: ...on magnets These magnets should not need to be adjusted 19 Remove the video amplifier board and main board as described previously 20 Remove the 4 screws V securing the CRT to the front casing of the monitor and release it from the casing 21 Remove the CRT aquadag D after releasing the spring keeping it taut A Fig 20 7 Replacing the Video Signals Cable D V V V V Fig 20 8 Removing the CRT 20 Video ...

Page 6: ...ments The sequence illustrated below should be performed step by step as some of the adjustments influence those that follow Video amplifier board VR301 Blue cut off VR302 Green cut off VR301 VR302 Fig 20 9 Video Amplifier Board Adjustments Video Unit Pocket Service Guide 20 6 14 COLOUR DISPLAY UNIT CDU 1435SE GS11 ...

Page 7: ...rizontal phase adjustment external access VR703 Sub contrast adjustment VR708 Horizontal size adjustment external access VR705 Sub brightness adjustment VR704 Contrast adjustment external access VR707 Horizontal center adjustment VR706 Brightness adjustment external access VR710 Side pincushion adjustment VR501 VR707 VR502 VR703 VR202 VR710 VR601 VR705 VR201 VR702 VR706 VR603 VR602 VR701 VR708 VR7...

Page 8: ...n main board to GND with short clip Connect the frequency counter between GND and R776 lead which is adjacent to pulse trans T901 Adjust the frequency to 31 45 KHz 100 Hz VERTICAL LINEARITY ADJUSTMENT System Test 640 BY 480 GRAPHICS CROSS HATCH PATTERN Adjust VR601 so that the vertically linearity should be best condition VERTICAL SIZE ADJUSTMENT System Test 640 BY 480 GRAPHICS Set the external V ...

Page 9: ...olor 0 0 Adjust the Sub Bright VR705 until the back raster disappears Confirm that back raster appears when the Bright VR706 is at Max CONTRAST ADJUSTMENT Set the external bright VR706 at center and the external contrast VR704 at Max Display White Pattern 700 mV input voltage of which the size is 90 x 90 on the monitor At the center of the screen adjust the Sub Contrast VR VR703 so that the bright...

Page 10: ...racter in full screen Set the bright VR at the center and the contrast VR at Max Adjust Focus VR on T702 transformer so that the focus should be best condition T702 Fig 20 16 Focus Adjustment Video Unit Pocket Service Guide 20 10 14 COLOUR DISPLAY UNIT CDU 1435SE GS11 ...

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