X-Ray Protection Circuit Check & Adjustments - Panasonic CT-32G6E Service Manual

IMPORTANT: To protect against possible damage to
the solid state devices due to arcing or static
discharge, make certain that all ground wires and CRT
DAG wire are securely connected.
CAUTION: The power supply circuit is above earth
ground and the chassis cannot be polarized. Use an
isolation transformer when servicing the Receiver to
avoid damage to the test equipment or to the chassis.
Connect the test equipment to the proper ground ( ) or
( ) when servicing, or incorrect voltages will be
measured.
WARNING: This Receiver has been designed to meet
or exceed applicable safety and X-ray radiation
protection as specified by government agencies and
independent testing laboratories.
To maintain original product safety design standards
relative to X-ray radiation and shock and fire hazard,
parts indicated with the symbol
must be replaced with identical parts. Order parts from
the manufacturer's parts center using the parts
numbers shown in this service manual, or provide the
chassis number and the part reference number.
For optimum performance and reliability, all other parts
should be replaced with components of identical
specification.
X-Ray Protection Circuit Check &
Adjustments
This test must be performed as final check before the
Receiver is returned to the customer. If voltages are
out of tolerance, immediate service and correction is
required to insure safe operation and to prevent the
possibility of premature component failure.
Equipment:
1. Isolation transformer.
2. High voltage meter.
3. Short jumper.
4. Jumper diode (same as D823, PN S3L60P154004).
Procedure:
1. Connect the Receiver to an isolation transformer.
2. Apply a monoscope pattern.
3. In Service Mode (see Service Mode Section in this
on the schematic
4. Measure TP5 (located near the tuner). Compare
5. Exit Service Mode and shut it OFF.
6. Connect the short jumper between TPD16 and
7. Connect the jumper diode between TPD14 and
8. Apply 75VAC to the input of the isolation
9. Turn Receiver ON.
10. Set PICTURE and BRIGHTNESS to minimum.
11. Slowly increase the voltage at the input of the
12. Turn Receiver OFF and remove jumper & diode.
- 5 -
Diode should be rated a minimum of 150V.
Turn Receiver ON.
manual) select register CB.
the measured value to the left column of the table
below. Set CB with value from the right column
corresponding to the measured level at TP5.
Example, if the measured level at TP5 is 1.03V, set
CB to 03.
TP5 MEASUREMENT
0 ~ 0.93V
0.93 ~ 0.97V
0.97 ~ 1.01V
1.01 ~ 1.05V
1.05 ~ 1.09V
1.09 ~ 1.13V
1.13 ~ 1.17V
1.17 ~ 1.21V
TPD17.
TPD15 (cathode connected to TPD14, anode
connected to TPD15, See Fig. 4 for locations).
transformer.
isolation transformer and confirm HHS voltage
measure 36.7KV when the Receiver starts to go
out of sync.
9.14
SET CB TO (HEX)
00
01
02
03
04
05
06
07