Safety Precautions; Warning - Harman Kardon AVR-134 Service Manual

WARNING

Before servicing this unit, familiarize yourself with the following precautions:
1. Many electrical and mechanical parts in this
chassis have special safety characteristics that
often pass unnoticed and the protection
afforded by them cannot necessarily be
obtained by using replacement components
rated for higher voltage, wattage, etc.
Replacement parts that have these special
safety characteristics are identified in this
manual and its supplements: electrical
components having such features are identified
by in the schematic diagram and the parts
list.
Before replacing any of these components, read
the parts list in this manual carefully. The use of
substitute replacement parts that do not have
the same safety characteristics as specified in
the parts list may create shock, fire, or other
hazards.
2. Before returning the set to the customer,
always do an AC leakage current check on the

SAFETY PRECAUTIONS

2
exposed metal parts of the cabinet, such as
terminals, screw heads, and metal overlays, to
be sure the set is safe to operate danger of
electrical shock. Plug the AC line cord directly
into a 120 V AC outlet(USA Version) or 230 V
AC outlet(EU Version). (Do not use a line
isolation transformer during this check.) Be
sure your AC voltmeter has a sensitivity of
5000 Ω per volt or greater. Then connect a
1500 Ω 10 watt resistor, paralleled by a 0.15
µF 150 V AC capacitor, between a known good
earth ground(such as a water pipe, or conduit)
and the exposed metallic parts, one at a time.
Measure the AC voltage across the combination
of a 1500 Ω resistor and a 0.15 µF capacitor.
Reverse the AC plug at the AC outlet and
repeat AC voltage measurements for each
exposed metalic part. Voltage measured must
not exceed 0.75 V RMS. This corresponds to
0.2 mA AC. Any value exceeding this limit
constitutes a potential shock hazard and must
be corrected immediately.