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C-Y21 EK

JVC C-VT14 EKB, C-V14 EKB, C-Y21 EK SERVICE MANUAL

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JVC C-Y21 EK

General Information

Also Covers C-VT14 EKB
C-V14 EKB

Recommended Safety Parts

Item Part No. Description
(C-VT21EKW/C-Y21EK) 9 102-321001-10 C.R.T. (ITC) (V501) A51EBVT13X01(VIDEOCOLOR) 27 108-890214-02 DEGAUSSING COIL ASS’Y
POLYPROPYLENE CAP 0.0056uF 1600V 5%
C807 026-152160-41 METALLIZED
POLYPROPYLENE CAP 0.0015uF 1600V 5% C901 026-473272-A5 METALLIZED PAPER CAP 0.047uF AC275V 20% C917 123-222467-42 C CAP. 2200pF 400V 20% T802 101-220009-04 20”/21” PAL FLYBACK (FCM-21A004) T901 001-419220-94B SWITCHING TRANSFORMER L902 001-190005-95C LINE FILTER BR901 130-310156-06 RECTIFIER LFARB156 Q802 031-242499-00 TRANSISTOR 2SD2499 Q904 031-242498-00 TRANSISTOR 2SD2498 F901 082-223150-23 FUSE 3.15A 250V S901 046-100007-00 POWER SWITCH TH901 014-210290-01 PTC THERMISTOR
061-520001-08 CRT SOCKET
(C-VT14EKW) 19 102-31400-13 C.RT(ITC)37SX110Y22-DC05 (IRICO)(V501) 21 108-400141-03 DEGAUSSING COIL 32 071-448254-20 AC CORD R807 013-338305-82 FLAME PROOF FUSING R 0.33* 1W 5% R808 013-109305-8E FLAME PROOF FUSING R 1* 1W 5% R813 013-688305-SD FLAME PROOF FUSING R 0.68* 1W J R915 013-825305-92 HIGH VOLTAGE R 8.2M* 1W 5% R933 013-338305-82 FLAME PROOF FUSING R 0.33* 1W 5% R937 013-688205-80 FLAME PROOF FUSING R 0.68* 1/2W C805 123-102850-40 C CAP 0.001uF 2KV 10% C806 026-562160-41 MET POLY. CAP. 0.0056uF 1600V 5% C807 026-222160-41 MET POLY. CAP 0.0022uF 1600V 5% C901 026-473272-A5 MET PAPER CAP. 0.047uF AC275V 20% C917 123-222487-42 C CAP. 2200pF 400V 20% T802 101-114002-04 FLYBACK TRANSFORMER FC-14A028A T901 001-419220-94 SWITCHING TRANSFORMER L902 001-190005-95C LINE FILTER BR901 130-310156-06 RECTIFIER LFARB156 Q802 031-242499-00 TRANSISTOR 2SD2499 Q904 031-242498-00 TRANSISTOR 2SD2498 F901 082-223150-23 FUSE 3.15A 250V S901 046-100007-00 POWER SWITCH TH901 014-210290-01 PTC THERMISTOR
(C-V14EKW) R807 013-338305-82 FLAME PROOF FUSING R 0.33* 1W 5% R808 013-109305-8E FLAME PROOF FUSING R 1* 1W 5% R813 013-688305-8D FLAME PROOF FUSING R 068* 1W J R916 013-625305-92 HIGH VOLTAGE R 8.2M* 1W 5% R933 013-338305-82 FLAME PROOF FUSING R 0.33* 1W 5% R937 013-688205-8D FLAME PROOF FUSING R 0.68* C901 026-473272-A5 MET PAPER CAP. 0.047uF AC275V 20% C917 123-222467-42 C CAP. 2200pF 400V 20% T802 101-114002-04 FLYBACK TRANSFORMER FCK-14A028A T901 001-419220-94 SWITCHING TRANSFORMER L902 001-190005-95C LINE FILTER Q802 031-242499-00 TRANSISTOR Q904 031-242498-00 TRANSISTOR 2SD2498 F901 082-223150-23 FUSE 3.15A 250V S901 046-100007-00 POWER SWITCH TH901 014-210290-01 PTC THERMISTOR
061-540019-01 CRT SOCKET 570-M21402-01 INSTRUCTION BOOK

Adjustments

BEFORE ADJUSTMENT AND MAINTENANCE
1. Don’t short any two soldering points or connect any component while TV set is power on.
2. Withdraw power plug before maintenance.
3. In order to ensure safety all components replaced should be identical. (For further details, refer to the component name and component No. in PARTS LIST.)
4. Must be warm up the set for 30 minutes or more and degauss CRT thoroughly with demagnetiser coil before adjustment.
EQUIPMENT FOR ADJUSTMENT
1. Pattern Generator
2. Digital voit meter
3. Oscilloscope
4. Demagnetiser
ADJUSTMENTS PROCEDURES +B ADJUSTMENT
1. Receive a standard colour bar signal.
2. Select the NORMAL on embody on VIDEO MENU to set controls at normal condition.
3. Connect digital voit meter between + of C811 and GND.
4. Adjust VR901 until meter reading DC 110V ±0.25V.
RF AGC ADJUSTMENT
1. Receive a broadcast.
2. Turn the RF AGC VR (VR201) so that noise appears on the screen.
3. Turn the RF AGC VR (VR201) until the noise disappears.
4. Change the channel and check that the picture is normal.
FOCUS ADJUSTMENT
1. Select the “NORMAL” in the VIDEO MENU to set controls at normal position.
2. Adjust knob “FOCUS” on FBT to make the picture on the screen to be the most distinct.
SERVICE MODE
A service mode facilitates for TV chassis alignment and repair in the field. Following the below step to entry the service mode.
1. Turn off the TV set main switch. (If the TV set at standby mode, turn on the set by remote control before turn off the main switch.)
2. Press the volume-up and volume-down buttons on the front panel simultaneously.
3. Turn on the main switch.
4. Wait about 6 seconds and the TV will display the service mode OSD menu as follows:
Fig. 1
5. Release the volume-up and volume-down buttons.
NOTE:
1. Entry the service mode only allow at the first 6 seconds of turn on the main switch. On the service mode the set can power on automati­cally and bypass the standby mode, it use for aging operation on mass production. Two ways to switch back to normal TV reception. One is using clear button, and the another way is pressing and hold on program up or down on front panel and then push main
power switch to turn TV off and on.
2. The current program number is displayed on the top left corner. The decimal value on the center of the second line is the parameter and the following is value.
The Program-up and Program-down buttons
select parameters while Volume-up and Volume-down buttons adjust the current value of parameters.
Parameter Description Device Minimum Maximum 1 Red Gain IC401 0 63
2 Red cut off (PAL) 063 3 Green Gain 063 4 Green cut off (PAL) 063 5 Blue Gain 063 6 Horizontal position 063 7 Vertical position 07 8 Vertical amplitude (50Hz) 063 24 OSD Vertical posltion 20 46 25 OSD Horizontal position 032 26 Sub brightness 016
• REPLACEMENT OF EEPROM
The CPU will automatic initialization the EEPROM contents when the blank new EEPROM is changed.
1. Change of blank new EEPROM.
2. Connect the main supply.
3. Power ON the main switch.
4. Press the remote stand-by button or program up button on the front panel.
5. Wait 6 seconds and the TV will turn on automatically (The CPU will blocked the TV set 6 seconds for EEPROM initialization). The service mode OSD menu will displayed on screen. Adjust the parameter as requested.
The following adjustment steps are in the service mode.
ADJUSTMENT FOR WHITE BALANCE
1. Receive a Black-White pattern RF signal.
2. Select “NORMAL” in VIDEO MENU to set Contrast and Brightness at normal position.
3. Enter service mode.
4. Set parameters of 2, 4 to value “32” and parameters of 1, 3, 5 to value “63”
5. SCREEN ADJUSTMENT
1) Receive a PAL black pattern.
2) Find out the highest cut off line level between the pin 9. 12. 15 of IC501 and connect the probe of oscilloscope on the highest cathode.
3) Adjust SCREEN VR to have DC160V ±2V using the black level.
6. Receive a Black-White pattern signal.
7. Change the parameter 5 to value “45” and parameters 1, 3 to value “32”.
8. Adjust the values of G-cut off and R-cut off and R-gain G-gain separately to make the dark and bright area to white.
9. Repeat above step 7. until both bright area and dark area meet white balance.
Fig. 2 HORIZONTAL AND VERTICAL POSITION
ADJUSTMENT
1. Receive a crosshatch pattern signal.
2. Select the parameter 6 “Horizontal position”
and adjust the horizontal position of the pattern for center.
3. Select the parameter 7 “Vertical position” and adjust the vertical position of the pattern for center.
VERTICAL AMPLITUDE ADJUSTMENT
1. Receive a crosshatch pattern signal.
2. Change the parameter 8 “Vertical amplitude” to slightly overscan the screen.
ON SCREEN POSITION ADJUSTMENT
1. Change the parameter 24 and 25 “OSD Vertical position and OSD Horizontal position” to make the arrows appear at four corner and at the center of horizontal and vertical position.
The End.
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