- 5 -
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
on the schematic
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).
Diode should be rated a minimum of 150V.
Procedure:
1.
Connect the Receiver to an isolation transformer.
Turn Receiver ON.
2.
Apply a monoscope pattern.
3.
In Service Mode (see Service Mode Section in this
manual) select register Cb.
4.
Measure TP5 (located near the tuner). Compare
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.
5.
Exit Service Mode and shut it OFF.
6.
Connect the short jumper between TPD16 and
TPD17.
7.
Connect the jumper diode between TPD14 and
TPD15 (cathode connected to TPD14, anode
connected to TPD15, See Fig. 4 for locations).
8.
Apply 75VAC to the input of the isolation
transformer.
9.
Turn Receiver ON.
10. Set PICTURE and BRIGHTNESS to minimum.
11. Slowly increase the voltage at the input of the
isolation transformer and confirm HHS voltage
measure 35.0KV for 25” models, 35.8KV for 27”
models using SAMSUNG CRT or 35.0KV for 27”
models using AMEC CRT when the Receiver starts
to go out of sync.
12. Turn Receiver OFF and remove jumper & diode.
TP5 MEASUREMENT
SET Cb TO (HEX)
0 ~ 0.93V
00
0.93 ~ 0.97V
01
0.97 ~ 1.01V
02
1.01 ~ 1.05V
03
1.05 ~ 1.09V
04
1.09 ~ 1.13V
05
1.13 ~ 1.17V
06
1.17 ~ 1.21V
07
Summary of Contents for CT27G6DE - 27" COLOR TV
Page 19: ... 19 Notes ...
