TX-51P100X, TX-51P100H, TX-51P100HL, TX-51P100HQ, TX-51P100HZ - Panasonic TV Service Manual (repair manual). Page 3

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1. It is advisable to insert an isolation transformer in

the AC supply before servicing a hot chassis.

2. When servicing, observe the original lead dress,

especially the lead dress in the high voltage cir-
cuits.
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. When the receiver is not to be used for a long

period of time, unplug the power cord from the AC
outlet.

5. Potential, as high as 34.5kV, is present when this

monitor is in operation. Operation of the Projection
Monitor without the rear cover involves the danger
of a shock hazard from the power supply. Servicing
should not be attempted by anyone who is not
thoroughly familiar with the precautions necessary
when working on high voltage equipment.  Always
discharge the anode of the projection tube to the
Projection Monitor chassis before handling the
tube.

6. After servicing make the following leakage current 

checks to prevent the customer from being
exposed to shock hazards.

1. Unplug the AC cord and connect a jumper

between the two prongs on the plug.

2. Turn on the Projection Monitor’s power switch.
3. Measure the resistance value, with an ohmmeter,

between the jumpered AC plug and each exposed
metallic cabinet part on the projection monitor,
such as screw heads, connectors, control shafts,
etc. When the exposed metallic part has a return
path to the chassis, the reading should be between
4 M

Ω

 and 20 M

Ω

.

When the exposed metal does not have a return
path to the chassis, the reading must be 

∞

.

1. Plug the AC cord directly into the AC outlet. Do not

use an isolation transformer for this check.

2. Connect a 2k

Ω

, 10W resistor, in series with an

exposed metallic part on the projection monitor
and an earth such as a water pipe.

3. Use an AC voltmeter, with high impedance type, to

measure the potential across the resistor.

4. Check each exposed metallic part, and measure

the voltage at each point.

5. Reverse the AC plug in the AC outlet and repeat

each of the above measurements.

6. The potential at any point should not exceed 1.0V

rms. In case a measurement is outside of the limits
specified, there is a possibility of a shock hazard,
and the projection monitor should be repaired and
rechecked before it is returned to the customer.

Warning :
1. The potential sources of X-Radiation in projection

monitor are the High Voltage section and the pro-
jection tube.

2. When using a projection tube test jig for service,

ensure that jig is capable of handling 32.5kV with-
out causing X-Radiation.

Note: It is important use an accurate periodically cali-

brated high voltage meter.

1. Set the brightness to minimum.
2. Set the service switch to the service position.
3. Measure the High Voltage. The meter reading

should indicate 34.5 ( ± 0.5 ) kV. If the meter indi-
cation is out of tolerance, immediate service and
correction is required to prevent the possibility of
premature component failure.

4. To prevent an X-Radiation possibility, it is essential

to use the specified projection tube.

AC Voltmeter

To
Instrument's
Exposed
Metallic Parts

2k

, 10W

Water Pipe
( Earth )

 !"#