Zenith C27C35T Series Service Manual page 4

PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS
SHUTDOWN CIRCUIT TEST
Equipment required:
a) K.V. DC meter (0 to 40 KV, high Z).
b) External variable power supply (0V to 8 VDC).
c) Shutdown Circuit.
Apply a voltage signal of an external power supply
through the shutdown circuit (Refer to Figure shown
below). Connect an accurate high voltage meter between
the picture tube anode and chassis ground. Access the
Video Menu and adjust Brightness and Contrast controls
for minimum screen luminance. Wait until the Video Menu
or display disappears. Read the high voltage meter,
ramping up the external power supply from 0 to 8 volts,
until the circuit shutsdown.
R1
100 Kohm
Red
External Power
Supply
0 - 8 Volts
Black
CM152
AV SHUTDOWN EXTERNAL
Q2
121-01187
R2
1 Kohm
SAFETY CIRCUIT TEST PROCEDURE
Equipment required:
a) K.V. DC meter (0 to 30 KV, high Z).
b) Video Generator
Before turning the TV on, connect the HV meter's nega-
tive probe (-) to ground (DAG ground recommended)
and the positive probe (+) in the anode of the CRT.
Apply a video signal or tune the TV to a crosshatch pat-
tern (either Lion or Convergence). Access the Video Menu
and adjust Brightness and Contrast controls for mini-
mum screen luminance. Wait until the Video Menu or
display disappears. Now, the high voltage meter shows
HV @ 0 beam.
R3
White
1 Kohm
Q1
121-01187
R4
220 Ohm
Black
iii
MODULE
RX3704
182K
White
ICX3406
RX3705
3.57K
Black
XC - SAFETY