Fluke 5725A, Instruction Manual, Page: 124 / 196

5725A
Instruction Manual
7-8
Problem 3: Fault When Entering Voltage Operate 7-6.
Proceed as follows to isolate the problem in this condition:
1. Suspect the 5700A/5725A interface cable.
2. Check the analog monitor circuit on the High Voltage Sense Assembly as in step 1
on conditions 1 and 2.
3. Suspect the High Voltage Amplifier assembly and the output transistor heat sink
assemblies.
Problem 4: Fault When Entering Current Standby 7-7.
Proceed as follows to isolate a problem in this condition:
1. If an overcompliance error is showing (fault 211), check for proper closing of the
standby relay on the Current assembly (K202).
2. Check the analog monitor circuit on the High Voltage Sense Assembly as in step 1
on conditions 1 and 2.
Problem 5: Fault When Entering Current Operate 7-8.
Proceed as follows to isolate a problem in this condition:
1. If an overcompliance error is showing (fault 212):
a. Check for an open or too high resistance load.
b. Suspect an open internal current output cable, or the Current Amplifier
assembly.
2. Check the analog monitor circuit on the High Voltage Sense Assembly as in step 1
on conditions 1 and 2.
Reduced-Voltage Troubleshooting Mode 7-9.
The high voltage supply on the Power Supply assembly (A4) allows normal operation
from a pair of nominal 400V dc supplies, or troubleshooting operation in a reduced
voltage mode with a pair of nominal 50V dc supplies. To switch between normal and
reduced-voltage operation, proceed as follows:
1. Turn off the POWER switch and disconnect the line power cord from ac line power.
Warning
Follow the instructions under "Initial Access Procedure" in
section 6 to make sure high voltage has been bled off before
you touch anything inside the 5725A.
The power supply assembly generates lethal voltages. Use
extreme caution when you are working inside the 5725A with
the power connected. Use only non-conductive tools, and keep
one hand behind your back to avoid making a circuit through
your body. If you work on a 5725A with the power cord
attached, and/or you are not certain the high voltage has not
bled off, do not wear a grounded wrist strap. Wearing a strap
increases risk of dangerous electrical shock.
2. Place the Power Supply assembly in the service position as described in the access
procedures in Section 6.