2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
105
3.5.4.2.1 A10 Port-2 Frequency Selection Error Test
1 Check SEL A on A10 with a DMM.
2 Verify that it is no greater than 2 volts.
QUESTION: Is the SEL A voltage 2 or less?
If Yes: Go to, 3.5.4.2.2.
If No: Remove power, replace A10, and retest.
3.5.4.2.2. A10 SEL-B Line Test
1 Remove instrument power.
2 Unsolder gray wire from SEL B terminal.
3 Reapply instrument power.
4 Check voltage on gray with DMM.
5 Verify that voltage is greater than 2 volts.
QUESTION: Is voltage greater than 2 volts?
If Yes: Remove power, replace A7, and retest.
If No: Remove power, replace A10, and retest.
3.5.5.0 A10 1 MHz Output Test
1 Connect the 1 MHz output connector on the rear panel to the 50 input of a
scope using coax. (If a 50 input is absent, use the high impedance input
with a 50 coaxial feedthrough terminator at the scope end of the coax).
2 Verify presence of a 1-MHz undistorted sine wave with at least
2.8 Vp-p amplitude.
QUESTION: Does the scope show a 1-MHz undistorted sine wave
with at least 2.8 Vp-p amplitude?
If Yes: Go to, 3.5.6.0
If No: Remove power, replace A10, and retest.