THORLABS MX40G Series, User Manual, Page: 39 / 44

MX40G, MX70G Series of E-O Converters Chapter 8: Maintenance, Repair, and Fuses
Rev. E, March 19, 2019 Page 35
8.3 Replacing the Main Fuse
The system is protected by a main fuse located in the power entry module where the main power cable plugs into the back
panel of the instrument. If the instrument does not appear to power-up, especially after a power outage or storm, you can
check the condition of the main power fuse without removing the cover of the instrument by following the following steps.
1. Put the instrument in “Standby” mode by pressing the standby button on the front of the instrument.
Wait until the button turns from green to amber.
2. Turn the power off using the switch on the back panel of the instrument.
3. Unplug the main power cable.
4.
Carefully remove the fuse holder slide from the power entry module (use a flat screwdriver)
.
Figure 50
Power Entry Module
Figure 51
Removing the Fuse Holder Slide
Investigate the fuse. This can be done with a simple continuity check. If in doubt, replace the fuse. A spare fuse is stored in the
fuse holder. Additional replacement fuses can be purchased from Thorlabs.
Always use fuses of the same type as the
original .
Figure 52 Fuse
1. Reinstall the fuse holder slide into the power entry module, taking care that it fully seats until the top is flush with the
rest of the power entry module.
2.
Plug the main power cable back into the unit and power on as described in the Getting Started section of the manual.
If the fuse blows repeatedly, it is likely that an internal failure has occurred. Do not attempt to bypass the fuse as this can create
a dangerous situation that could further damage the instrument or harm personnel. In this case, please contact Technical Support
for directions.