3
1 Safety Precaution
1.1.
General Guidelines
1. IMPORTANT SAFETY NOTICE
There are special components used in this equipment which are important for safety. These parts are marked by (!) in the
Schematic Diagrams, Circuit Board Layout, Exploded Views and Replacement Parts List. It is essential that these critical parts
should be replaced with manufacturer’s specified parts to prevent X-RADIATION, shock fire, or other hazards. Do not modify
the original design without permission of manufacturer.
2. An Isolation Transformer should always be used during the servicing of AC Adaptor whose chassis is not isolated from the AC
power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal
injury from electrical shocks. It will also protect AC Adaptor from being damaged by accidental shorting that may occur during
servicing.
3. When servicing, observe the original lead dress. It a short circuit is found, replace all parts which have been overheated or
damaged by the short circuit.
4. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly
installed.
5. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.
1.1.1.
Leakage current cold check
1. Unplug the AC cord and connect a jumper between the two prongs on the plug.
2. Measure the resistance value, with an ohmmeter, between the jumpered AC plug and each exposed metallic cabinet part on
the equipment such as screwheads, connectors, control shafts, etc. When the exposed metallic part has a return path to the
chassis, the reading should be between 1M
Ω
and 5.2M
Ω
. When the exposed metal does not have a return path to the chas-
sis, the reading must be infinity.
1.1.2.
Leakage current hot check (See Figure 1)
1. Plug the AC cord directly into the AC outlet. Do not use
an isolation transformer for this check.
2. Connect "A" to exposed metallic part on the set. And con-
nect "B" to a good earth ground, as shown in Figure 1.
3. Use an AC voltmeter, with 1 k
Ω
/V or more sensitivity, to
measure the potential across the resistor.
4. Check each exposed metallic part, and measure the volt-
age 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 0.75 V RMS.
A leakage current tester (Simpson Model 229 or equiva-
lent) may be used to make the hot checks, leakage cur-
rent must not exceed 1/2 mA. 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.
Figure 1
Summary of Contents for NV-MD10000
Page 9: ...9 4 Specifications ...
Page 10: ...10 5 Location of Controls and Components ...
Page 11: ...11 ...
Page 18: ...18 Fig D1 Fig D2 Fig D3 Fig D4 ...
Page 19: ...19 Fig D5 Fig D6 Fig D7 Fig D8 ...
Page 20: ...20 Fig D9 Fig D10 Fig D11 ...
Page 21: ...21 Fig D12 Fig D13 Fig D14 Fig D15 ...
Page 22: ...22 Fig D16 Fig D17 Fig D18 ...
Page 23: ...23 Fig D19 Fig D20 Fig D21 Fig D22 ...
Page 24: ...24 Fig D23 Fig D24 Fig D25 Fig D26 ...
Page 25: ...25 Fig D27 Fig D28 Fig D29 ...
Page 26: ...26 Fig D30 Fig D31 Fig D32 ...
Page 27: ...27 Fig D33 Fig D34 ...
Page 28: ...28 Fig D35 ...
Page 30: ...30 Fig M3 ...
Page 31: ...31 Fig M4 Fig M5 ...
Page 32: ...32 Fig M6 ...
Page 39: ...39 Fig E3 Rough image of set up connection ...
Page 40: ...40 Fig E4 Extension cables VFK1317 2pcs Measuring Board VFK1308E 232C I F Cable VFK1395 ...
Page 44: ...44 Fig D2 Fig D3 ...
Page 52: ......
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