Keithley 2700, Service Manual

Page: 67 / 174

Calibration 2-19
Extender board preparation
Before performing manufacturing calibration, short the output HI, LO, SHI, and SLO
terminals of the 7798-250B Calibration/Extender/Test Board together using clean, solid copper
wires. These connections will form a low-thermal short necessary for the manufacturing
calibration procedure. The Calibration Extender Test Board should then be installed in scanner
Slot #1.
Unlocking manufacturing calibration
To unlock manufacturing calibration, press and hold in the OPEN key while turning on the
power.
Measuring function generator signal amplitude
The 3Hz function generator signal amplitude must be accurately measured using the digital
multimeter listed in Table 2-13 . Proceed as follows:
1. Connect the function generator output to the digital multimeter INPUT jacks. (See
Figure 2-5 for typical connections.)
2. Turn on the function generator and multimeter, and allow a two-hour warm-up period
before measuring.
3. Set the function generator to output a 1V RMS sine wave at 3Hz; measure and record
the signal amplitude.