Samsung MM-X7, Service Manual

1. Precautions

Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards
such as electrical shock and X-rays.

Samsung Electronics

1-1

1-1 Safety Precautions

1. Be sure that all of the built-in protective

devices are replaced.  

2. When reinstalling the chassis and its 

assemblies, be sure to restore all protective

devices, including control knobs and 

compartment covers.

3. Make sure that there are no cabinet 

openings through which people--
particularly children--might insert fingers

and contact dangerous voltages.  Such
openings include the spacing between the
picture tube and the cabinet mask, 

excessively wide cabinet ventilation slots,

and improperly fitted back covers.

4. Design Alteration Warning:

Never alter or add to the mechanical or
electrical design of the unit. Example: Do
not add auxiliary audio or video connec-
tors. Such alterations might create a safety
hazard. Also, any design changes or addi-
tions will void the  manufacturer's warran-
ty.

5. Leakage Current Hot Check (Figure 1-1):

Warning: Do not use an isolation 
transformer during this test.  Use a leakage-

current tester or a metering system that
complies with American National Standards
Institute (ANSI  C101.1, 

Leakage Current for

Appliances

), and Underwriters Laboratories

(

UL Publication UL1410, 59.7

).

With the unit completely reassembled, plug

the AC line cord directly into a 120V AC
outlet.  With the unit's AC switch first in
the ON position and then OFF, measure the
current between a known earth ground
(metal water pipe, etc.) and all exposed
metal parts.  Examples: Handle brackets,
metal cabinets, screwheads and control
shafts.  The current measured should not
exceed 0.5 milliamp.  Reverse the power-
plug prongs in the AC outlet and repeat.

6. 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, antenna, control shafts or 
handle brackets.

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

Device
Under 

Test

(Reading should
not be above
0.5mA)

Leakage
Currant
Tester

Earth
Ground

Test all

exposed metal

surfaces

Also test with
plug reversed
(using AC adapter
plug as required)

2-Wire Cord

Antenna
Terminal

Exposed
Metal Part

ohm

Ohmmeter

Fig. 1-1 AC Leakage Test

Fig. 1-2 Insulation Resistance Test