Servicing
DC Power Supply Replacement
Thermo Fisher Scientific
Model 42
i
Trace Level Instruction Manual
7-29
Note
If Service Mode is not displayed, refer to “
Accessing the Service
Mode
” on page
7-4
, then return to the beginning of this step.
▲
2.
At the Input Board Calibration screen, press
to select Manual
Input Cal, and press
to calibrate.
The screen displays the frequency at GAIN 1.
3.
Make a note of the FREQ value displayed at GAIN 1, then press
or
to change the GAIN to 100.
4.
At the GAIN 100 screen, use
to increment the D/A counts
until the FREQ value matches or is slightly above (within 50 counts)
the value noted in the previous step.
5.
Press
to store the value.
The screen flashes
Calculating - Please Wait!
and
Done - Values
Saved!
messages.
Use the following procedure to replace the DC power supply (
Figure 7–
15
).
Equipment Required:
DC power supply
Philips screwdriver
Equipment Damage
Some internal components can be damaged by small
amounts of static electricity. A properly grounded antistatic wrist strap
must be worn while handling any internal component.
▲
1.
Turn instrument OFF, unplug the power cord, and remove the cover.
2.
Disconnect all the power supply electrical connections. Note connector
locations to facilitate re-connection.
3.
Loosen the captive screw securing the power supply to the chassis plate
and lift out the power supply.
DC Power Supply
Replacement
