DOWNLOAD Panasonic AG-TL750E / AG-TL750B Service Manual ↓ Size: 11.71 MB | Pages: 90 in PDF or view online for FREE

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1.  When servicing, observe the original lead dress. If a

short circuit is found, replace all parts which have been
over-heated or damaged by the short circuit.

2.  After servicing, see to it that all the protective devices

such as insulation barriers, insulation papers shields are
properly installed.

3. 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. Measure the resistance value, with an ohm meter,

between the jumpered AC plug and each exposed
metallic cabinet part on the equipment such as
screwheads, connectors, control shafts, etc. The
resistance value must be more than 5M

Ω

.

1. Plug the AC cord directly into the AC outlet.

Do not use an isolation transformer for this check.

2. Connect a 1.5K

Ω

, 10W resistor, in parallel with a 0.15

µ

 F

capacitor, between each exposed metallic part on the set
an a good earth ground such as a water pipe, as shown
in Figure1.

3. Use an AC voltmeter, with 1000 ohms/volt or more

sensitivity, 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 repeat each of the

above measurements.

6. The potential at any point should not exceed 0.15 volts

RMS. A leakage current tester (Simpson Model 229
equivalent) may be used to make the hot checks,
leakage current must not exceed 0.1 milliamp. In case a
measurement is outside of the limits specified, there is a
possibility of a shock hazard, and the equipment should
be repaired and rechecked before it is returned to the
customer.

Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically sensitive (ED) Devices. Examples of
typical ES devices are integrated circuits and some field-
effect transistors and semiconductor “chip” components. The
following techniques should be used to help reduce the
incidence of component damage caused by static electricity.
1. Immediately before handling any semiconductor

component or semiconductor-equipped assembly, drain
off any electrostatic charge on your body by touching a
known earth ground.
Alternatively, obtain and wear a commercially available
discharging wrist trap device, which should be removed
for potential shock reasons prior to applying power to the
unit under test.

2. After removing an electrical assembly equipped with ES

devices, place the assembly on a conductive surface
such as alminum foil, to prevent electrostatic charge
buildup or exposure of the assembly.

3. Use only a grounded tip soldering iron to solder or

unsolder ES devices.

4. Use only an anti-static solder removal device classified

as “anti-static” can generate electrical charges sufficient
to damage ES devices.

5. Do not use freon-propelled chemicals. These can

generate electrical charges sufficient to damage ES
devices.

6. Do not remove a replacement ES device from its

protective package until immediately before you are
ready to install it.
(most replacement ES devices are package with leads
electrically shorted together by conductive foam,
alminum foil or comparable conductive material).

7. Immediately before removing the protective material from

the leads of a replacement ES device, touch the
protective material to the chassis or circuit assembly into
which the device will be installed.
CAUTION : Be sure no power is applied to the chassis or
circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged

replacement ES devices. (Otherwise hamless motion
such as the brushing together of your clothes fabric or
the lifting of your foot from a carpeted floor can generate
static electricity sufficient to damage an ES device).

WARNING
1. The potential source of X-radiation in EVF sets is the

High Voltage section and the picture tube.

2. When using a picture tube test jig for service, ensure that

jig is capable of handling 10kV without causing X-
Radiation.

It is important to use an accurate periodically
calibrated high voltage meter.

3. Measure the High Voltage. The meter (electric type)

reading should indicate 2.5kV,±0.15kV. If the meter
indication is out of tolerance, immediate service and
correction is required to prevent the possibility of
premature component failure. To prevent an X-Radiation
possibility, it is essential to use the specified picture tube.

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1-1

A

A

Top Cover

S1

S1

The following flow chart shows the disassembly procedures for
the PC board assembly diagnostics and mechanism diagnos-
tics. Be sure to unplug the power cord before disassembling or
assembling the products.

Removing the Top Cover (Section 1.1.3)

START

Removing the Front Panel assembly (Section 1.1.4)

Removing the Bottom Cover (Section 1.1.5)

Removing the Cassette Housing

assembly (Section 1.1.6)

Removing the Mechanism

assembly (Section 1.1.7)

Mechanism diagnostics

Diagnostics of Major 

PC Boards (Section 1.2)

PC board assembly diagnostics

(1) Set the power switch to OFF and unplug the power cord

from the power outlet before replacing the fuse.

(2) Remove the top cover (see section 1.1.3).
(3) Fuse F1 is located on the SW REG board.

F1

SW REG board

Rear side

(1) Remove the 4 screws 

S1

.

(2) Remove the top cover by sliding it in the direction of arrow.

(1) Remove the top cover as described in section 1.1.3.
(2) Disengage the 4 hooks 

Å

 on the front panel assembly from

the chassis.