Lake Shore 350, User Manual

Page: 188 / 192

174 c
HAPTER
8: Service
Model 350 Temperature Controller
8.11.2 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:
D
De-energize or disconnect all power and signal sources and loads used with unit.
D
Place the unit on a grounded conductive work surface.
D
The technician should be grounded through a conductive wrist strap (or other
device) using 1 M series resistor to protect operator.
D
Ground any tools, such as soldering equipment, that will contact the unit. Con-
tact with the operator’s hands provides a sufficient ground for tools that are oth-
erwise electrically isolated.
D
Place ESD sensitive 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.
D
Do not handle ESD sensitive devices unnecessarily or remove them from the
packages until they are actually used or tested.
8.12 Enclosure Top
Remove and
Replace Procedure
Follow this procedure to remove the top enclosure. The enclosure top remove and
replace procedure if for installing an input option card.
To avoid potentially lethal shocks, turn off the controller and disconnect it from AC power
before performing these procedures.
The components on this board are electrostatic discharge sensitive (ESDS) devices.

Follow ESD procedures in section 8.11 to avoid inducing an electrostatic discharge (ESD)
into the device.
1. Turn the Model 350 power switch Off. Unplug the power cord from the wall out-
let, then from the instrument.
2. Stand the unit on its face. Use a 5/64 in hex driver to remove the four screws on
both sides of the top cover. Loosen the two rear bottom screws (FIGURE 8-10).
Cover removal
Remove
rear
plastic
bezel
Remove top
side cover
screws
(both sides)
Loosen
bottom
rear
side cover
screws
(both sides)
Remove top
cover screws
To remove
top cover,
slide it to
the rear
on the
tracks
Remove
rear
bottom
cover
screw
(unshown)
3. Use a small Phillips screwdriver to remove the two top cover screws and one rear

bottom screw (FIGURE 8-10).
4. Remove the rear plastic bezel. The cover is tracked. Slide the top cover to the rear
on the track to remove it.
FIGURE 8-10