Introduction; General Troubleshooting; Starting With A Dead Tester (Model 41B Only) - Fluke 39 Service Manual

5-1. Introduction

This chapter describes troubleshooting procedures that can be used to isolate problems
with the Tester. These procedures deal primarily with the digital section of the Tester.
Due to the simplicity of the Analog section, only theory of operation is provided to
support analog troubleshooting.
When troubleshooting the Tester, follow the precautions listed on the "Static
Awareness" sheet to prevent damage from static discharge.
Signal names followed by "*" are active (asserted) low. Signal names not so marked are
active high.

5-2. General Troubleshooting

To avoid contaminating the pca with oil from your fingers,
handle the pca by its edges or wear gloves. A contaminated
pca may not cause immediate instrument failure in controlled
environments. Failures typically show up when contaminated
units are operated in humid areas.
Before starting to troubleshoot, make sure the batteries are fresh enough to meet the
minimum power supply voltages specified in Table 5-2.
5-3.

Starting with a Dead Tester (Model 41B Only)

When the Tester is turned on, the display should flash dark and then come up in either
the waveform, harmonics, or text screen mode. If it does not, it is possible that someone
left the display contrast very low, causing the display to be blank. To eliminate this
possibility, hold down R while pressing o and then release both buttons.
If the Tester still appears dead, the problem could be in the power supplies or power-on
circuit, the digital kernel, or the display module itself. Use the appropriate procedure
below to isolate the problem.
Caution
Troubleshooting
5

Introduction

5-3