Denon DN-A7100 - AV Surround Preamplifier, Руководство по обслуживанию

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Please heed the points listed below during servicing and inspection.
◎ Heed the cautions!
Spots requiring particular attention when servicing, such as
the cabinet, parts, chassis, etc., have cautions indicated on
labels or seals. Be sure to heed these cautions and the cau-
tions indicated in the handling instructions.
◎
Caution concerning electric shock!
(1) An AC voltage is impressed on this set, so touching inter-
nal metal parts when the set is energized could cause
electric shock. Take care to avoid electric shock, by for ex-
ample using an isolating transformer and gloves when
servicing while the set is energized, unplugging the power
cord when replacing parts, etc.
(2)There are high voltage parts inside. Handle with extra care
when the set is energized.
◎ Caution concerning disassembly and assembly!
Though great care is taken when manufacturing parts from
sheet metal, there may in some rare cases be burrs on the
edges of parts which could cause injury if fingers are moved
across them. Use gloves to protect your hands.
◎
Only use designated parts!
The set's parts have specific safety properties (fire resis-
tance, voltage resistance, etc.). For replacement parts, be
sure to use parts which have the same properties. In particu-
lar, for the important safety parts that are marked ! on wiring
diagrams and parts lists, be sure to use the designated parts.
◎
Be sure to mount parts and arrange the
wires as they were originally!
For safety reasons, some parts use tape, tubes or other insu-
lating materials, and some parts are mounted away from the
surface of printed circuit boards. Care is also taken with the
positions of the wires inside and clamps are used to keep
wires away from heating and high voltage parts, so be sure to
set everything back as it was originally.
◎ Inspect for safety after servicing!
Check that all screws, parts and wires removed or discon-
nected for servicing have been put back in their original posi-
tions, inspect that no parts around the area that has been
serviced have been negatively affected, conduct an insulation
check on the external metal connectors and between the
blades of the power plug, and otherwise check that safety is
ensured.
(Insulation check procedure)
Unplug the power cord from the power outlet, disconnect the
antenna, plugs, etc., and turn the power switch on. Using a
500V insulation resistance tester, check that the insulation re-
sistance between the terminals of the power plug and the ex-
ternally exposed metal parts (antenna terminal, headphones
terminal, microphone terminal, input terminal, etc.) is 1M
Ω
or
greater. If it is less, the set must be inspected and repaired.
Concerning important safety parts
Many of the electric and structural parts used in the set have
special safety properties. In most cases these properties are
difficult to distinguish by sight, and using replacement parts
with higher ratings (rated power and withstand voltage) does
not necessarily guarantee that safety performance will be pre-
served. Parts with safety properties are indicated as shown
below on the wiring diagrams and parts lists is this service
manual. Be sure to replace them with parts with the designat-
ed part number.
(1) Schematic diagrams ... Indicated by the ! mark.
(2) Parts lists ... Indicated by the ! mark.
Using parts other than the designated parts
could result in electric shock, fires or other
dangerous situations.
SAFETY PRECAUTIONS
The following check should be performed for the continued protection of the customer and service technician.
LEAKAGE CURRENT CHECK
Before returning the unit to the customer, make sure you make either (1) a leakage current check or (2) a line to chassis
resistance check. If the leakage current exceeds 0.5 milliamps, or if the resistance from chassis to either side of the power
cord is less than 460 kohms, the unit is defective.
CAUTION
CAUTION