To Next Page

To Previous Page

2. Service

Assembly/Module Diagnostic Trees (Diagnostic Section 3)

A2 Hot-Wire Ionizer Diagnostic Tree

This functional subsection describes the A2 hot-wire ionizer diagnostic tree

for the 5071A Primary Frequency Standard. Performance of these tests is

indicated by the presence of either a self-test or fatal error that reports a hot-

wire ionizer fault.

3.1.1.1.0 CBT Hot-Wire Resistance Test

1 Power off the 5071A.

2 Unplug cable from A2J1 and A2J2.

3 Using a 4-wire Ohm Meter, measure the resistance across pins

1 and 6 on the CBT cable.

QUESTION: Is the resistance between 0.1 and 0.25 ?

If Yes: Go to, 3.1.1.1.1.

If No: Recheck results and Ohmmeter, then replace CBT.

3.1.1.1.1 CBT Hot-wire Resistance-to-Ground Test

1 Measure the resistance across pins 1 and 4 on the CBT cable.

QUESTION: Is the resistance greater than 200 k?

If Yes: Go to, 3.1.1.1.2.

If No: Recheck results and DMM, then replace CBT.

3.1.1.1.2 Hot-Wire Monitor Test (No Current)

1 Remove instrument power.

2 Remove A2 CBT Controller.

3 Install the long extender board (05071-60052) into A2 slot.

4 Turn on the 5071A.

5 Use SCPI command syst:print?.

(Terminal-to-instrument via RS-232C data communication required.)

QUESTION: Is HW Ionizer: between -0.5 and +0.5 V?

If Yes: Go to, 3.1.1.1.3.

If No: Remove power, replace A7, and retest.

Symmetricom 5071A Assembly And Service Manual

Other manuals for Symmetricom 5071A