Lake Shore Model 218 Temperature Monitor User’s Manual
Service
7-1
CHAPTER 7
SERVICE
7.0 GENERAL
This chapter provides general service information for the Model 218 Temperature Monitor. There is no
calibration procedure for the Model 218. There are no serviceable parts inside the Model 218. Contact
Lake Shore about specific problems with the Model 218.
7.1 GENERAL MAINTENANCE PRECAUTIONS
Below are general safety precautions unrelated to any other procedure in this publication. These are
recommended precautions that personnel should understand and apply during the maintenance phase.
Keep away from live circuits. Installation personnel shall observe all safety regulations at all times. Turn
off system power before making or breaking electrical connections. Regard any exposed connector,
terminal board, or circuit board as a possible shock hazard. Discharge charged components only when
such grounding results in no equipment damage. If a test connection to energized equipment is
required, make the test equipment ground connection before probing the voltage or signal to be tested.
Do not install or service equipment alone. Do not reach into or enter any enclosure to service or adjust
the equipment without another person capable of rendering aid.
If there is no power, verify the power cord is plugged into a live outlet and that both ends are securely
plugged in. Next, check the fuse (refer to Paragraph 3.3.1.1).
Clean the Model 218 periodically to remove dust, grease and other contaminants as follows:
1. Clean front/back panels and case with soft cloth dampened with mild detergent and water solution.
NOTE:
Do
not
clean with aromatic hydrocarbons or chlorinated solvents. They may react with the
plastic materials used in the controller or the silk screen printing on the back panel.
2. Clean surface of printed circuit boards (PCBs) with clean, dry air at low pressure.
7.2 ELECTROSTATIC
DISCHARGE
Electrostatic Discharge (ESD) may damage electronic parts, assemblies, and equipment. ESD is a
transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct
contact or induced by an electrostatic field. The low-energy source that most commonly destroys
Electrostatic Discharge Sensitive (ESDS) devices is the human body, which generates and retains
static electricity. Simply walking across a carpet in low humidity may generate up to 35,000 V of static
electricity.
Current technology trends toward greater complexity, increased packaging density, and thinner
dielectrics between active elements, which results in electronic devices with even more ESD sensitivity.
Some electronic parts are more ESDS than others. ESD levels of only a few hundred volts may
damage electronic components such as semiconductors, thick and thin film resistors, and piezoelectric
crystals during testing, handling, repair, or assembly. Discharge voltages below 4,000 V cannot be
seen, felt, or heard.
7.2.1 Identification of Electrostatic Discharge Sensitive Components
Below are various industry symbols used to label components as ESDS:
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