CT-34WX50 — Panasonic TV Service Manual (repair manual)

Model
CT-34WX50
Pages
58
Size
10.31 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / PX1T
File
ct-34wx50.pdf
Date

View Panasonic CT-34WX50 Service Manual online

Weight (Mass)
174.0lbs (79kg) Net
Connection terminals
AV INPUT 1-4
VIDEO 1.0Vp-p (75
)
(Phono Jack Type)
S-VIDEO Y:1.0Vp-p 
(75
)
(Mini DIN 4-pin)C:0.286 Vp-p (75
)
AUDIO L-R 0.5 Vrms
(Phono Jack Type x 2)
AV PROG. OUT
VIDEO 1.0Vp-p (75
)
(Phono Jack Type)
S-VIDEO
Y:1.0 Vp-p (75
)
(Mini DIN 4-pin)C:0.286 Vp-p (75
)
AUDIO L-R 0.5 Vrms
(Phono Jack Type x 2)
TO AUDIO AMP
AUDIO L-R 0.5 Vrms
(Phono Jack Type x 2)
COMPONENT VIDEO
INPUT1-2
Y 1.0 Vp-p (including synchronization)
P
B
/P
R
 
 0.35 Vp-p
AUDIO L-R 0.5 Vrms
(Phono Jack Type x 2)
Design and Specifications are subject to change without
notice.
Weight and Dimensions shown are approximate.
Specifications
Power Source
AC120V, 60Hz
Power Consumption:
Average use: 193.7 W (Maximum Current: 3.7
Stand-by condition: 0.36W
CRT
34-inch, 16:9 aspect ratio (Viewing area)
Applicable signals
Color system : NTSC
Screen size
29.36”(745.9mm)(W)x16.5”(419.5mm)(H)x33.68”(855.7mm)(D)
ANODE Voltage
33.0±1.0kV at zero beam current
Accessories Supplied
Remote control  EUR511162
Battery (2xR6 (AA) Size)
Warranty
Speaker Out
5 Speakers
21W(7W+7W+7W) (10% THD)
Impedance 8
Dimension (WxDxH)
34.4”(874mm) x 23.0”(585mm)x25.1”(637mm)
ã
ORDER NO.ITD0001002C1
Wide Screen TV
CT-34WX50
PX1T Chassis
The service technician is required to read and follow the “Safety Precaution” and “Important Safety Notice” in this service manual.
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- 3 -
Safety Precautions
General Guidelines
1.
It is advisable to insert an isolation transformer in the AC
power line before servicing a hot chassis.
2.
When servicing, observe the original lead dress, espe-
cially the lead dress in the high voltage circuits.  If a
short circuit is found, replace all parts which have been
overheated or damaged by the short circuit.
3.
After servicing, see to it that all the protective devices
such as insulation barriers, insulation papers, shields,
and isolation R-C combinations, are properly installed.
4.
Before switching the power on, measure the resistance
between B+ line and cold side chassis ground.  Connect
the “-” side of an ohmmeter to the B+ line, and the “+”
side to chassis ground.  Each line must have more resis-
tance value than the specified one as follows:
5.
When the set is not used for a long period of time,
unplug the AC power cord plug from the AC line outlet.
6.
High voltage points, as high as 33 ± 1.0 kV, are present
when the set is in operation. Operating the set without
the rear cover involves in a dangerous electrical shock
from the set power supply. Servicing must not be
attempted by anyone who is not thoroughly familiar with
the necessary precautions when working on high volt-
age equipment. Always discharge the anode of the pic-
ture tube to chassis ground before handling the picture
tube.
7.
After servicing, make the following leakage current
checks to prevent the customer from dangerous electri-
cal shock.
Leakage Current Cold Check
1.
Unplug the AC power cord and short between the two
prongs of the AC plug with a jumper wire.
2.
Set the power switch of this set to ON position.
3.
Measure the resistance value with an ohmmeter
between the shorted AC plug and each exposed metallic
part of the set cabinet such as screwheads, connectors,
and control shafts. When the exposed metallic part has
a return path to the chassis, the reading should be more
than 1 M
.
When the exposed metal part does not have a return
path to the chassis, the reading must be infinity.
Leakage Current Hot Check (See Fig.1)
1.
Plug the AC power cord directly into the AC line outlet.
Do not use an isolation transformer for this check.
2.
Connect a 1.5k
, 10W resistor, in parallel with a 0.15µF
capacitor between each exposed metallic part of the set
and an earth ground such as a water pipe.
3.
Use a high impedance AC voltage meter to measure the
voltage across the resistor.
4.
Measure the voltage at each exposed metallic part.
5.
Reverse the AC plug inserting direction at the AC line
outlet and repeat each of the above measurements.
6.
The voltage at any point must be less than 0.75Vrms.
7.
A leakage current tester (Symptom Model 229 or the
equivalent) may be used to make the hot checks.  In this
case, the current must be less than 500µA.
8.
If the reading is more than the above value, the set must
be repaired and rechecked before it is returned to the
customer because of a possibility of an electrical shock.
X-Radiation
Warning:
1.
The potential sources of X-Radiation in the monitor set
are the high voltage section and picture tube.
2.
When using a picture tube test jig for service, make sure
that jig is capable of handling 32.5kV without causing X-
Radiation.
3.
For continued X-radiation protection, in case that at least
one of the components listed below is replaced, follow
the adjustment procedure of the high voltage circuit.
Precise adjustment is necessary for R720 to protect X-
Radiation.  Refer to “High Voltage and X-Radiation Pro-
tective Circuit Adjustment section”.
T551, IC457, IC5508, D512, R520, R521, R522, R809,
R810, R5568, C481, C528, RL001
B+ line
Minimum Resistance
220V(TPD7)
10k
144V(TPD17)
10k
23V(TPD25,33)
3k
15V(TPD20)
5k
12V(TPD23)
50k
Hot-Check Circuit
Fig. 1
AC Voltmeter
To
Instrument’s
Exposed
Metallic Parts
1.5k
, 10W
0.15
µ
F
Water Pipe
( Earth )
- 4 -
HOLD DOWN OR SAFETY CIRCUIT
INFORMATION
To monitor the high voltage, the positive DC voltage from the
cathode D512 is applied through R788 and other resistors to
pin 3 of IC475, which is the input terminal of the X-ray Pro-
tection Circuit. The voltage at pin 2 of IC457 is adjusted by
R720 at 5.83 +0.01, -0.02 voltage. Under normal conditions
this voltage is insufficient to activate the X-ray Protection Cir-
cuit.
If the voltage at pin 3 of IC457 increases over the voltage at
pin 2 of IC457 increases and causes the X-ray Protection to
activate. Then it causes the shut down works.
In the process described above, the voltage at pin 3 of IC457
is compared with the voltage at pin 2 of IC457.
if excessive beam current is drawn, the voltage at oin 3 of
IC457 increases. When the voltage at pin 3 of IC457 over the
voltage at pin 2 of IC457, the voltage at pin 1 of IC457
becomes “high” and feeds into Base of Q401, and the volt-
age at Corrector of Q401 becomes “high” and feeds into pin
38 of micro-controller IC5508 through R5618.
The micro-controller then turns off Q802, causes the AC
power relay RL001 to unlatch and turns off the receiver.
Service Instruction: Procedure to apply
silicone to the seal control R720
Purpose
To prevent any adjustment on the sealed control after final
adjustment is done at factory. If the sealant are removed
for any reason, the control is damaged at same time.
Material
1. Silicone-Type T8C1710201H, manufactured by Shin-Etsu 
Chemical Co., Ltd. (Japan)
2. Hard ABS tube-Type TMMX004
Tools
No tool is required.
Procedures
1. Place the hard ABS tube on the designated sealed con-
trol,
as shown in Figure a.
Figure a.
2. When the tube is gently pressed all the way down and
adhere to the P.C.B., apply the silicon into the hard ABS
tube and form hemisphere like object on the top of tube, a
shown in Figure b.
Figure b.
6
1
+
-
X-Ray Detect
38
7
1
2
3
12V
R809
Q802
R810
R5568
IC5508
R5618
R770
C481
R773
R720
R522
R788
R521
D512
FBT T551
R520
C528
R721
12V
EHT
CRT
IC457
AC POWER RELAY
RL001
Comparator Ref.
Comparator out
Comparator in
Silicone
Page of 58
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Here you can view online or download Panasonic CT-34WX50 Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Panasonic CT-34WX50 TV. Information contained in Panasonic CT-34WX50 service manual (repair manual) typically includes:

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  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).