Sony KZ-32TS1U Training Manual page 62

F1601
R1654
6.3A
R1655
G BD.
LAMP COMES ON
1 WHEN CN1908/PIN 1 = 5V
2 POWER BLOCK BD.
OUTPUTS 27kV IGNITION
VOLTAGE , THEN 25kV RUN
VOLTAGE
LAMP DEFECTIVE -
STBY LED BLINKS CONTINUOUSLY
POWER BLOCK BD. DEFECTIVE -
STBY LED BLINKS 5 TIMES
LAMP COVER SW. OPEN -
STBY LED BLINKS 3 TIMES
New HV Detector Circuit
The purpose of the HV Detector circuit (on the M board) is to identify the cause of no backlight. The front panels
LEDs use this information. The LAMP LED blinks continuously if the lamp is defective or the Standby LED will
blink five times if the HV or control circuitry is bad. Refer to Figure 27-1 for the following HV detector circuit
description:
Normal Operation - At power ON, Main Micro IC9004 instructs Lamp Control IC9502 (both on M board) to output
a HIGH at Ctl (A board, CN1908/pin 1). This HIGH is applied to the Power Block to start the 25kV necessary for
the lamp ignition. If the lamp starts to draw current, the Power Block closes the relay to reduce lamp voltage and
grounds the PRT line (CN1908/pin 3 or the end gray wire on the Power Block).
The PRT (protect) line is a signal to tell the Main Micro the lamp is drawing current (working). When LOW
(0Vdc), the Main Micro in turn unmutes the A/V lines and a picture with sound appears (all within 20 seconds after
turn ON).
Defect - The LAMP LED blinks continuously - The main Micro looks at the PRT signal (CN1908/pin 3) and the
antenna signal to determine if the lamp or Power Block is defective (Table 27-1). When HV appears without a
load (bad bulb), arcing in the spark gap on the Power Block creates RF that is picked up by the nearby antenna
wire. This RF signal is brought back to the A board at CN1908/pin 12. The RF signal only passes through the A
board to get to the M board (CN9501/pin 50) where it is rectified. On the M board, a DC voltage developed after
the RF signal is rectified indicates the presence of HV (normal Power Block operation). If there is HV and no
current draw, the conclusion is that the lamp is bad so the Main Micro continuously blinks the front panel LAMP
LED.
R1613
270V
+
1
2
N/C
*
-
3
255V-
*
CN1602
350V
POWER
SUPPLY
CTL=
ON=5V
OFF=0V
A BD.
CN1920/
CN9501
M BD.
FIGURE 27-1 - LAMP CONTROL - KF-60DX100
SPARK GAP
POWER
G1
BLOCK BD.
25kV TO GAS
DISCHARGE
LAMP
WIRE
HV
COLOR
DET
WHI GRY
0V
PRT
=0V
3
1 2 3 12 13 4 5
40
40 39 50 49
0V
S DATA
5V
IC9502 LAMP
CONTROL
CLK
HV DET
WIRE
60
27. Grand Wega Lamp Control
LAMP COVER
T BD.
BOARD
S8001
N/C
CN1908 CN1901
4 4
7 7
CN
48 45
4502
IC9004
MAIN
MICRO
TV FRONT
POWER
M BD.
BLOCK
HV
2
1
G1
6TVP13 1439
H3 BD.
POWER
STBY LED
TV
BLOCK
4/16/02