user manual

136 Chapter 9
Service
Troubleshooting
Troubleshooting
Refer to Chapter 1, “Introduction and Installation,” to make sure the test set is
connected properly to the analyzer and that the analyzer has been configured for use
with the multiport test set.
Troubleshooting consists of isolating the cause of any problem to an individual
assembly. The multiport test set has three main assemblies:
•power supply
• LED display board
• main switch board assembly
WARNING Line voltage may be present on exposed metal heat-sinks and other
components contained on the power supply. Observe all safety precautions.
The Power Supply
WARNING For continued protection against fire hazard, replace fuse only with same type
and ratings (H 3.15 A, 250 VAC). The use of other fuses or materials is
prohibited.
The line fuse is located on the power supply assembly. See the parts list (later in this
chapter) for the fuse part number. The power supply is autoranging and will accept
from 90 to 254 volts AC. The power supply provides ±15 volts and +5 volts to the
main board assembly via a four wire cable assembly. The pin-out is as follows:
Pin # Voltage Wire Color
LED
Ref. Designator
1 +15 volts brown DS701
3 +5 volts orange DS700
4 ground yellow N/A
6 −15 volts blue DS702