HP 2040D - Manual (Page 6)

Series 2040 Test System
Series 2040 Maintenance Manual V2.00 Maintenance Overview
5
SYSTEM MAINTENANCE OVERVIEW
The Series 2040 Test System has been designed with extensive diagnostics and
self testing capabilities. Each module and circuit board includes additional
circuitry for calibration and self testing programs. In addition, a Selftest
Assembly is provided to calibrate and functionally test every component in the
test system. This assembly attaches to the fixture interface to provide the best
accuracy and reliability for calibration and self-diagnostics.
The Certification program uses a Calibration station containing a Digital
Voltmeter (DVM) and Universal Counter/Timer, which are certified by the
National Institute of Standards and Technology as a “Transfer Standard,” to
calibrate the internal precision references of the tester. The Selftest Assembly
uses a 18-bit D/A converter (TDAC) as an internal precision voltage standard.
The internal precision time standard is a Temperature Compensated Crystal
Oscillator located on the Time Measurement System board.
The Calibration and Selftest routines calibrate the remainder of the system to
the tester’s internal precision references. Calibration constants are derived
during Calibration. These constants are used during runtime to maintain
system accuracy. The Calibration constants are stored on the hard drive and
reloaded at powerup. Complete system auto-calibration is achieved without
any pots to adjust.
The Selftest programs use the Selftest Assembly to test all circuits to their
published specifications, and assure that all paths and modules are functional.
The System Maintenance guide is written for troubleshooting to the module
and circuit board level.
The tester shall be disconnected from all power sources
before it is opened for any adjustment, replacement,
maintenance or repair. If service repairs performed under
power become necessary, the repairs shall be performed
by a skilled technician who is aware of the hazard
involved.