CONFIDENTIAL
1 Precautions
Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as electrical shock.
1-1 Safety Precautions
1.For continued safety, do not attempt to modify the circuit board.
2.Disconnect the AC power and DC Power Jack before servicing.
1-1-2 Servicing the LCD Monitor
1.When servicing the LCD Monitor disconnect the AC line cord from the AC outlet.
|
|
|
| (READING SHOULD | |||
|
|
|
| NOT BE ABOVE 0.5mA) | |||
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
| LEAKAGE |
| |
DEVICE |
|
|
|
|
| ||
|
|
|
| CURRENT |
| ||
UNDER |
|
|
|
|
| ||
|
|
|
| TESTER |
| ||
TEST |
|
|
|
|
|
|
|
|
|
| TEST ALL | ||||
|
| EXPOSED METAL | |||||
|
|
| SURFACES | ||||
|
2.It is essential that service technicians have an accurate voltage meter available at all times. Check the calibration of this meter periodically.
1-1-3 Fire and Shock Hazard
Before returning the monitor to the user, perform the following safety checks:
1.Inspect each lead dress to make certain that the leads are not pinched or that hardware is not lodged between the chassis and other metal parts in the monitor.
2.Inspect all protective devices such as nonmetallic control knobs, insulating materials, cabinet backs, adjustment and compartment covers or shields, isolation
3.Leakage Current Hot Check (Figure
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).
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)EARTH GROUND
Figure 1-1. Leakage Current Test Circuit
4.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, conduit, etc.) and all exposed metal parts, including: metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5 milliamp. Reverse the
the test.
1-1-4 Product Safety Notices
Some electrical and mechanical parts have special
!on schematics and parts lists. A substitute replacement that does not have the same safety characteristics as the recommended replacement part might create shock, fire and/or other hazards. Product safety is under review continuously and new instructions are issued whenever appropriate.
LTM1555(B)/LTM1755(B) |