Specifications
Chapter 4: Troubleshooting
Power Supply Troubleshooting
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Figure 4-15 Trigger ICs fan on backplane assembly
Apply AC power and turn the oscilloscope on if it does not start up on its own. Notice
whether the trigger ICs fan is turning. If it is not, replace it and redo this part of the
diagnostic test. If it is turning and the oscilloscope still turns off again, then consider
these possibilities:
• If the trigger ICs fan was turning, the problem is most likely that the rotation sensor
on the ICs fan is defective. Replace the trigger ICs fan and redo this part of the
diagnostic test.
• If the oscilloscope stays on after you reset the shutdown logic (by removing AC power
for 30 seconds) and powered it back on, then you have fixed the shutdown problem.
• If the oscilloscope shuts down again after you have replaced the trigger ICs fan, then
the problem could be that the rotation sensor for all the fans located on the backplane
assembly failed, so replace the backplane assembly and redo this part of the diagnostic
test.
If the L- ACQ TEMP FAIL or U- ACQ TEMP FAIL LED is Lit
If the oscilloscope shuts down and either the L- ACQ TEMP FAIL or U- ACQ TEMP FAIL
indicator LEDs is lit, then one of the scope channels is getting too hot or the temperature
sensing circuitry has failed. Normally, you would have to turn the oscilloscope on and
leave it on for awhile before you would see a shutdown caused by temperature problems.
If all the fans are turning, it is unlikely that the oscilloscope would shut down due to
temperature unless the airflow is being restricted or the input air is already too hot
to cool the insides of the oscilloscope.
It is possible that all the case fans and the trigger ICs are working, but the oscilloscope
still shuts down because of temperature due to one or more of the channels
malfunctioning and drawing too much current. If so, you would need to replace the
indicated acquisition assembly. It is also possible for one of the heat sinks on one of
the acquisition assemblies' critical parts to become detached and cause that part to
overheat and shut down the oscilloscope.