Tektronix 371B Service Manual page 43

Test Fixture Interlock
371B Service Manual
Readout intensity is controlled by the READOUT/CURSOR knob; label
intensity is controlled by the GRAT ILLUM knob.
NOTE. The READOUT/CURSOR control also controls the intensity of other
information displayed on the screen, which may include text, messages, and
setup and curve identification.
Test Fixture Unit. All tests are made with the semiconductor device mounted
inside the test fixture unit. The test fixture unit connects to the front panel of the
main unit.
The test fixture unit contains a patch panel and an adapter panel that are enclosed
by a clear plastic cover during the actual testing process. The DUT connects to
the patch panel in one of two ways.
H Using test adapters. Test adapters are used to connect common semiconduc-
tor devices to the adapter panel, which in turn is connected to the patch panel
using patch cords.
H Using patch cords. Devices that cannot be connected using test adapters can
be connected to the patch panel using patch cords with clips. In such cases,
the adapter panel may have to be removed.
The test fixture connects to the main unit using the interconnect cable and
connector. The top row of connectors on the patch panel are linked internally to
the connector cable.
The test fixture unit is provided with a safety interlock system. Whenever the test
fixture cover is in the raised position, the collector supply voltage is disabled and
you can safely connect and disconnect devices at the patch panel and the adapter
panel. When the cover is closed the collector supply voltage is enabled. The
enabled state is indicated by a red WARNING indicator on the 371B. When lit,
the WARNING indicator indicates that the collector supply is enabled and that a
dangerous voltage may appear at the patch panel terminals on the test fixture
unit.
WARNING. Do not disable the safety interlock system and then attempt to operate
the 371B. You may accidentally contact high voltage and serious personal injury
or death may result.
The collector supply is also disabled whenever the test fixture unit cable is
disconnected from its connector at the front panel of the main unit.
General Information
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