Regulation; Testing For Low B+ Or Shutdown - Sony KD-34XBR2 Training Manual

Item Checkpoint (use Hot Gnd except noted)
340Vdc (B+) D board
CN6501/pin 1 /
Fusible R6526
Pri Pre 15V D board
voltage CN6501/pin 5
Main Relay D board
voltage CN6504/pin 2 =
4.9Vdc (cold Gnd)
Surge Relay D board
PH6503/pin 4 =
6.3Vdc
PH6503
CN6501/6
Hot GND
FBT
HA-3 Chassis - D Board

Regulation

The +135V line to the Horizontal Output stage is fed back to IC6501 for regulation of the secondary power supply.
Error Control IC6503 and Optical Isolator PH6502 control regulation. If the +135V output rises, the voltage at
IC6501/pin 2 lowers to correct. A reduced voltage increases the oscillator frequency and decreases the output
voltages of T6501.

Testing for Low B+ or Shutdown

The typical error correction feedback voltage at IC6501/pin 2 is 2Vdc. By verifying the +135V B+ at R6598 and
measuring the feedback at IC6501/pin 2, you can determine if the problem is in the basic oscillator stage or in the
error regulator stage. See Chart 7-2, Chart 7-3 and Chart 7-4 on the following page:
Chart 7-1 - Items Needed to Start the Secondary Power Supply
HA-3 Direct View RA-5A PJ TV
G board
Fusible R6041
G board
IC6001/pin 8
G board
CN6101/pin 6 =
5V (cold Gnd)
G board
PH6003/pin 4 =
4.5Vdc
4
3
7. Secondary Power Supply - HA-3 & RA-5A Chassis
From
Bridge Rectifier D6530 Powers the Driver/Output
Primary Power Supply
secondary – Pri Pre
Main Micro IC001 (B
board)
Primary Power Supply
secondary -Sub 7V or
Sub 6.5V
CN6504/1
AC in
RA-5A Chassis - G Board
Figure 7-2
Checkpoint
Locations
21
Purpose
Starts the oscillator when
more than 15.6Vdc.
Enables Sec PS Osc
IC6501 when HIGH
Stop the secondary PS if
the Surge Relay does not
close after power ON.
CN6501/6
PH6003
3 4
IC6001
R6041