Operating Environment - Tektronix TDS 420A Service Manual

Memory Backup Power

Operating Environment

Operating Temperature
Ventilation Requirements
TDS 420A, TDS 430A & TDS 460A Service Manual
CAUTION. Before stepping the source line voltage from one range to a higher
range, set the principal power switch (rear panel) to its OFF position. Failure to
do so can damage the oscilloscope.
There are two fuses. Either fuse may be used throughout the line voltage and
frequency ranges. These two fuses are not totally interchangeable as each
requires a different fuse cap. The fuses and their caps are listed by part number in
Chapter 10, Mechanical Parts List.
Replaceable lithium batteries maintain internal memory modules to allow the
digitizing oscilloscope to retain the following data upon loss of the AC power
source: stored adjustment constants, saved front-panel settings, current front-pa-
nel settings (oscilloscope status), and saved waveforms.
These batteries have a shelf life of about five years. Partial or total loss of stored
settings upon powering on may indicate that you need to replace the batteries.
The following environmental requirements are provided to ensure proper
operation and long oscilloscope life.
Operate the oscilloscope where the ambient air temperature is between 0_ C and
+50_ C, and store the oscilloscope at an ambient temperature from - -40_ C to
+75_ C. After storage at temperatures outside the operating limits, allow the
chassis to stabilize at a safe operating temperature before applying power.
The digitizing oscilloscope is cooled by air drawn in and exhausted through its
cabinet side panels by an internal fan. To ensure proper cooling of the oscillo-
scope, allow at least 50.8 mm (2 inches) clearance on both sides and 19 mm
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@
( inch) on the bottom of the digitizing oscilloscope. (The feet on the bottom of
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the oscilloscope provide the required clearance when set on flat surfaces.) The
top of the oscilloscope does not require ventilation clearance.
CAUTION. If air flow is restricted, the power supply of the digitizing oscilloscope
may temporarily shut down.
Installation
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