Samsung HT-F4500, Service Manual

Page: 5 / 65

1. Precaution
5) Insulation Resistance Cold Check :
(1) With the unit’s AC plug disconnected from the AC source, connect an electrical jumper across the two AC prongs.
(2) Set the power switch to ON.
(3) Measure the resistance between the shorted AC plug and any exposed metallic parts.
Example : Screwheads, Metal Cabinets, Antenna Port, etc. If any of the exposed metallic parts has a return path to
the chassis, the measured resistance should be between 1 and 5.2 megohms. If there is no return path, the measured
resistance should be “infinite”. If the resistance is outside these limits, a shock hazard might exist.
See
Figure 1.2 Insulation Resistance Test
Ante nn a
Term ina l
oh m
Expo se d
Meta l Pa rt
Ohmme te r
Figure 1.2 Insulation Resistance Test
6) Components, parts and wiring that appear to have overheated or that are otherwise damaged should be replaced with
parts that meet the original specifications. Always determine the cause of damage or overheating, and correct any
potential hazards.
7) Observe the original lead dress, especially near the following areas :
Antenna wiring, sharp edges, and especially the AC and high voltage power supplies. Always inspect for pinched,
out-of-place, or frayed wiring. Do not change the spacing between components and the printed circuit board. Check the
AC power cord for damage. Make sure that no wires or components touch thermally hot parts.
8) Product Safety Notice :
Some electrical and mechanical parts have special safety-related characteristics which might not be obvious from visual
inspection. These safety features and the protection they give might be lost if the replacement component differs from
the original–even if the replacement is rated for higher voltage, wattage, etc.
9) Components that are critical for safety are indicated in the circuit diagram by shading, or .
Use replacement components that have the same ratings, especially for flame resistance and dielectric strength
specifications. A replacement part that does not have the same safety characteristics as the original might create
shock, fire or other hazards.
Copyright© 1995-2012 SAMSUNG. All rights reserved. 1-2