Lake Shore Model 218 Temperature Monitor User’s Manual
7-2
Service
EU_Fuse.bmp
Figure 7-1. Fuse Drawer
F-218-7-2.eps
Figure 7-2. Power Fuse Access
7.2.2 Handling Electrostatic Discharge Sensitive Components
Observe all precautions necessary to prevent damage to ESDS components before attempting installation.
Bring the device and everything that contacts it to ground potential by providing a conductive surface and
discharge paths. As a minimum, observe these precautions:
1. De-energize or disconnect all power and signal sources and loads used with unit.
2. Place unit on a grounded conductive work surface.
3. Ground technician through a conductive wrist strap (or other device) using 1 M
Ω
series resistor to protect
operator.
4. Ground any tools, such as soldering equipment, that will contact unit. Contact with operator's hands
provides a sufficient ground for tools that are otherwise electrically isolated.
5. Place ESDS devices and assemblies removed from a unit on a conductive work surface or in a
conductive container. An operator inserting or removing a device or assembly from a container must
maintain contact with a conductive portion of the container. Use only plastic bags approved for storage of
ESD material.
6. Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested.
7.3 FUSE
DRAWER
The fuse drawer supplied with the Model 218
holds the instrument line fuses and line voltage
selection module. The drawer holds two 5
×
20 mm time delay fuses. It requires two good
fuses of the same rating to operate safely.
Fuse ratings are the same for the line voltages.
Refer to Paragraph 7.5.
7.4 LINE VOLTAGE SELECTION
Use the following procedure to change the
instrument line voltage selector. Verify the fuse value whenever line voltage is changed.
WARNING: To avoid potentially lethal shocks, turn off controller and disconnect it from AC power
before performing these procedures.
1. Identify the line input assembly on the instrument rear panel. See Figure 7-2.
2. Turn the line power switch OFF (
O
).
3. Remove the instrument power cord.
4. With a small screwdriver, release the
drawer holding the line voltage selector
and fuse.
5. Slide out the removable plastic fuse holder
from the drawer.
6. Rotate the fuse holder until the proper
voltage indicator shows through the
window.
7. Verify the proper fuse value.
8. Re-assemble the line input assembly in the
reverse order.
9. Verify the voltage indicator in the window
of the line input assembly.
10. Connect the instrument power cord.
11. Turn the line power switch On (
l
).
