Kenwood KT-CV500 Service Manual

TV TUNER

KTC-V500E/N/P

SERVICE MANUAL

KTC-V500E

4-CHANNEL DIVERSITY TV TUNER

TV ANTENNA INPUT

TO MONITOR UNIT

The following reference numbers with accessory parts are the same reference numbers used on EXPLODED VIEW and PARTS LIST.

DC1

ANTENNA SW

TUNER

VIF

SAW

CIRCUIT

DIVERSITY VIDEO

DEMODULATOR

VIF

VIDEO

MATRIX

RGB SW

DEMODULATOR

VIF

SAW

SIF

DEMODULATOR

MIX

DEMODULATOR

OSC

NOISE CANCELLER

LPF SOUND (L/R)

6dB

6dB 75

RGB-OUT

VIDEO

8V AVR

14.4V

ACC

AVR

IC401 IC400

Q103

Q101

IC300

IC200

IC301

IC504

IC502

IC202

IC203

IC700

ACC 5V

Q702

8V AVR

Q703

5V AVR

Q705

Q704

A 8V

V 8V

V 5V

A 5V

IC701

DC/DC

+30V

Q701

REGULATOR

POWER SUPPLY

KTC-V500E/N/P (E/K/M)

NTSC

PAL

SECAM

SYNC

DECODER

SDA SCL

SCL

SDA

OTHERSL': 38.9MHz

: 33.9MHz

BG : 33.4MHz

: 32.9MHz

DK/L

: 40.4MHz

: 32.4MHz

FM/AM

D/K

B/G I

22.7MHz

21.7MHz

22.2MHz

FM/AM

P. ON

10.7MHz

KTC-V500E/N/P

BLOCK DIAGRAM

KTC-V500E/N/P

ELECTRIC UNIT (X25-928x-xx)

REF. No. FUNCTION OPERATION

IC200 TV VIF/CHROMA Detects VIF, and processes chroma. IC202 VIDEO AMPLIFIER Amplifies G and B signals up to 6dB at 75 ohms. IC203 VIDEO AMPLIFIER Amplifies SYNC and R signals up to 6dB at 75 ohms. IC300 TV VIF/SIF Detects VIF and SIF (Euro model’s one is for diversity). IC301 AM DETECTION Detects SIF (AM). IC400 VIDEO SW Switches diversity video signal. IC401 TV DIVERSITY Switches TV antenna. IC502 OPERATION AMPLIFIER LPF & amplifier. IC504 NOISE CANCELER Cancels noise. IC700 AVR 5V local regulator. IC701 DC/DC REGULATOR Switches DC/DC voltage. IC702 AVR 8V local regulator. IC800 SYSTEM u-COM Controls functions. IC801 RESET IC Resets system u-com.

Q100 IF SW Switches SAW filter input IF. Q101 SIF AMPLIFIER Amplifies SIF. Q102 IF SW Switches SAW filter input IF.

Q103 VIF AMPLIFIER Amplifies VIF. Q201,202 BUFFER Creates H-sync pulse. Q203,204 BUFFER Buffers video signal. Q205-207 RGB MUTE Mutes RGB signals. Q208-210 RGB BUFFER Buffers RGB signals. Q211,212 VIDEO BUFFER Buffers video signal. Q300-302 CLOCK SW Switches clock. Q303,304 VIDEO BUFFER Buffers video signal.

Q305 SYNC PIF SW Switches sync PIF frequency. Q306,307 S-METER DC AMPLIFIER Amplifies s-meter DC.

Q308 VIDEO BUFFER Buffers video signal.

Q309 VIDEO MUTE Mutes TV video signal.

Q400 VIDEO MODE SW Switches diversity video mode.

Q401 ADJUST MODE SW Switches diversity adjustment mode. Q500,501 AUDIO MUTE Mutes audio signal.

Q700 Q701 DRIVER Drives Q701.

Q701 POWER SW Switches back-up power supply.

Q702 8V AVR Supplies power to TV front-end and IF circuit.

Q703 8V AVR Supplies power to IC200.

Q704 5V AVR Supplies power to TV front-end and IC301.

Q705 5V AVR Supplies power to video circuit.

Q706 B.U. DETECTION Detects back-up.

Q800 PANEL/BASS RESET SW Controls reset for panel and bass.

COMPONENT DESCRIPTION

KTC-V500E/N/P

(X25-) IC800 : SYSTEM u-COM

PORT NAME I/O FUNCTION OPERATING CONDITION

1 DIV O Diversity adjustment mode (Test mode). "H" : Adjustment mode on (Diversity forced off).

2-4

---

O IF switch (When state of PAL-D).

"H" : DK area.

6 IF IF switch (Group 3 when state of PAL-I).

"H" : I area.

BG OOIF switch (Group 1/2 when state of PAL-B/G)

"H" : BG area.

VDD

5V power supply.

10 X2

Main system clock oscillation (12.28MHz)

12 VSS

GND.

13,14

---

RESET

System reset.

"L" : Reset.

SC-CON I

Communication between panel and box.

17 MC-REQ I Communication between panel and box.

B.U. I Back-up detection.

"H" : B.U. OFF. "L" : B.U. ON.

19 P.ON O Power-on.

"H" : P.ON OFF. "L" : P.ON ON.

20,21

---

22 REF.CON O A/D converter reference voltage.

ADC comparator power supply switch.

AVDD

A/D converter analogue power supply.

24 AVREF 0

A/D converter reference voltage.

SD I SD.

S-METER I S-meter.

27-32

33 AVSS

GND.

34,35

---

36 AVREF 1

- Analogue reference voltage.

37 FLASH 1 O Flash 1.

38 FLASH 2 O Flash 2.

FLASH 3

O Flash 3.

40-43

---

44 SC REQ O Communication request in panel.

MC DATA I Communication data in panel.

46 SC DATA O Communication data in panel.

MC CLK I Communication clock in panel.

L2 O Video reception switch (Only in France)

"L" : VHF receiving. "H" : 2,3,4CH receiving.

50 AM/FM O AM/FM audio reception switch.

"L" : AM (Only in France). "H" : FM (Without France).

51,52

53 TYPE 1 I Destination switch.

"L" : For in Europe. "H" : For in Japan.

54-58

PLL-DATA O PLL data.

PLL-CLK O PLL clock.

PLL-ENB O PLL enable.

62 TV/V MUTE O TV tuner mute / Video mute.

"H" : Mute on. "L" : Mute off.

63-71

72 VSS

GND.

73-78

79 SP MUTE O Speaker audio line mute.

"L" : Mute on. "H" : Mute off.

81,82 VDD - Power supply.

83-86

87 TIME O

Waiting configuration for communication beginning with machro IC.

"L" : No waiting. "H" : 3 seconds waiting.

88-93

94 TEST

VPP voltage for flash memory writing.

"L" : Usual operation. "H" : Flash memory writing .

95-98

99 SCL O IC2 clock.

100

SDA I/O IC2 data.

MICROCOMPUTER'S TERMINAL DESCRIPTION

PORT

No.

ADJUSTMENT

X25 Circuit Adjustment Specification (K : For North American Markets)

Item A djustment method / Adjustment value Conditions

1. Video detection coil

adjustment

L303

1. Turn VR301 [RF-AGC] fully to the right.

2. Apply DC2.0V to TP [IF AGC] (IC300 pin36).

3. Feed fo=45.75MHz, Mod=1kHz, AM60%, Level=100dBµ into TP [IF]

(A100 pin8).

4. Observe the TP [VIDEO] (IC300 pin8) waveform on an oscilloscope and

adjust L303 for maximum level.

Maximum

No ANT signal

If the waveform is clipped,

slightly increase the DC

voltage.

AC range

2. Audio detection coil

adjustment

L300

1. Turn VR301 [RF-AGC] fully to the right.

2. Feed fo=41.25MHz, No Modulation, Level=94dBµ into TP [IF] (A100

pin8).

3. Connect a voltmeter to TP [SIF] (both ends of R314) and adjust L300 for 0V ± 0.01V.

No ANT signal

3. S-METER adjus tment

VR300

4. RF AGC adjustment

VR301

1. Turn VR301 [RF-AGC] fully to the right.

2. Feed a 30dBµ 11CH color bar RF signal into the ANT input terminal.

3. Audio (P/S ratio -6dB) no modulation.

4. Connect a voltmeter to CN300 and adjust VR300 [SMET] so it reads

3.5V ± 0.05V.

5. Set the RF signal to 70dBµ and adjust VR301 [RF-AGC] so that the

voltmeter connected to CN300 reads 4.5V ± 0.05V.

ostpone adjus ting VR301

to prevent AGC having effect at 30dBµ.

Ensure the RF AGC

adjustment is performed

after the S-METER

adjustment.

5. Diversity free run

frequency adjustment

VR400

1. Connect a frequency counter to CN400.

2. Using the remote control unit TV/NAVI button, switch to adjustment

mode.

3. Adjust VR400 [15kHz] so as to obtain 15734 ± 10Hz.

No ANT signal

Test mode

X25 Circuit Adjustment Specification (E : For European Markets)

Item A djustment method / Adjustment value Conditions

1. Diversity video detection

coil adjustment

L303

1. Input RF signal 70dBµ 9CH stair step into the ANT input terminal.

2. Observe the TP [VIDEO] (IC300 pin8) waveform on an oscilloscope and

adjust L303 so that the edges of sync chip and pedestal are horizontal.

PAL B/G

Turn color off.

2. Audio detection coil

adjustment

L300

1. Input RF signal 70dBµ 9CH bar into the ANT input terminal.

2. Connect a voltmeter to TP [SIF] (both ends of R314) and adjust L300 for 0V ± 0.01V.

PAL B/G

P/S ratio 10dB

3. Diversity free run

frequency adjustment

VR400

1. Connect a frequency counter to CN400.

2. Using the remote control unit TV/NAVI button, switch to adjustment

mode.

3. Adjust VR400 [15kHz] so as to obtain 15625 ± 10Hz.

No ANT signal

Test mode

KTC-V500E/N/P

NG OK NG

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