Upgrading The Firmware - Tektronix Keithley 2281 Series Reference Manual

Appendix A: Maintenance
Perform the following steps to replace the line fuse:
1. Power off the instrument.
2. Remove the line cord.
3. Locate the fuse drawer, which is next to the AC receptacle as shown in the graphic below.
4. Use the screwdriver to lift the tab from the AC receptacle.
5. Slide the fuse drawer out. The fuse drawer must be pulled completely out of the power module.
6. Snap the fuse out of the drawer.
7. Replace the two fuses.
8. Push the fuse drawer back into the power module.
If the power line fuses continue to become damaged, a circuit malfunction exists and must be
corrected. Return the instrument to Keithley Instruments for repair.

Upgrading the firmware

To upgrade the 2281S firmware, you load an upgrade file into the instrument. You can load the file
from the USB port using the front panel of the instrument.
The USB flash drive must be less than or equal to 2 GB and formatted in the FAT file format.
During the upgrade process, you must select whether you are upgrading to a newer firmware version
or downgrading to an older firmware version. The instrument will verify that the version you are
loading is newer or older depending on your selection.
The upgrade process should take about five minutes.
A-2
Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
Figure 132: Line fuse
077114601 / March 2019