32
9. High Voltage Power Supply
High Voltage Power Supply
This HV Converter is similar to the two low-voltage power supplies because they both have the same MCZ3001D
ICs. This power supply differs only in the start up, voltage output and over voltage (OV) protection. The Flyback
Output transformer of this power supply generates regulated 31.5kV and focus voltage for the CRT. Excessive
current drawn by this stage will permit Q8009 to shut down the TV set, but there will be no Standby light blink
indication. Refer to Figure 9-1 for the overview and Figure 9-2 for the description.
IC8001
PROTECT
LATCH
Q8009
OCP
IC8002
HV DRIVER
OUTPUT FBT
HV
ADJ.
D BOARD
ABL
SAMPLE
200V
SEC PS
(D BD.)
D6515
AFC PULSE
FROM
H OUT
Q5030/C
(D BD.)
D8014
FOCUS
VOLTAGE
TO PIX TUBE
31.5kV
HV TO
PIX
TUBE
D8027
D8003
200V
0V
Q6530, Q6532
SHUTDOWN
LATCH ONLY
(D BD.)
FIGURE 9-1 - HA-3 HV BLOCK
55TVP12 1369
8/30/01
Start UP
Three items listed in Chart 9-1 are necessary to start this HV power supply:
Chart 9-1 - HV Converter Inputs (Starting)
Name
From
Destination
1. +200V
D6515 & D6517 / cathode(D Bd) IC8002/18 (199V)
2. +15V
D6514 / cathode (D Bd)
IC8002/8 (14.7V)
3. AFC-
PLS
H Out Q5030/C (D Bd)
(CN5501/pin 3 = 9Vp-p
IC8002/1 (1.6V)
The Start sequence is as follows:
•
The Primary power supply produces low voltages for the Horizontal stage (D board).
•
The Secondary power supply pr135V for the Horizontal stage, along with +200V and +15V for this
HV Converter stage.
•
The Horizontal Output stage is needed to develop AFC-PLS pulses (CN5501/pin 3 = 9Vp-p) for the HV
Converter.
•
AFC-PLS pulses turn ON Q8001 and turn OFF Q8002.
•
IC8002/pin 1 voltage rises to 1.8V. (1.3Vdc is the minimum to start IC8002).
•
IC8002’s oscillator starts and drives the flyback transformer.
•
The voltage at IC8002/pin 2 decreases from 4V to 2Vdc as the HV climbs to 31.5kV.
•
Regulated HV and focus voltage output the flyback transformer.
Содержание KD-34XBR2 - 34" Hdtv Fd Trinitron Wega
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