Appendix A: Maintenance
Models 707B and 708B Switching Matrix Reference Manual
A-2
707B-901-01 Rev. B / January 2015
Check fan status
You can check the status of the fan from the front panel of the Model 707B.
In addition, if the fan is not operating on power up, the message "Failed to sense fan" is displayed.
To check the fan status:
1. From the front panel, select
MAIN MENU > UNIT-INFO > FAN
.
2. Press the navigation wheel. The status is displayed:
Fan Normal: Fan is operating normally.
Fan Failure: Fan is not moving.
3. Press
EXIT
to return to the menu.
If the fan is not operating, contact Keithley Instruments. See
Contacting support
(on page 8-10).
Fuse replacement
The fuses on the Model 707B or 708B are located on the rear panel of the instrument, as shown
below.
Replacement fuses are listed in the following table.
Replacement fuses
Model
Rating
Keithley Instruments part number
707B
250V, dual 2.0A slow blow
Two FU-106-2.0
708B
250V / 1.0A slow blow
One FU-72
Disconnect all external power from the equipment and the line cord before performing any
maintenance on the Model 707B or 708B.
Failure to disconnect all power may expose you to hazardous voltages, that, if contacted,
could cause personal injury or death. Use appropriate safety precautions when working
with hazardous voltages.
To replace a fuse:
1. Use a small flat-tip screwdriver to lift the tab at the bottom of the fuse module.
2. Pull the fuse module out.
3. Replace the fuse.
4. Re-install the fuse module.
If the fuse continues to blow, a circuit malfunction exists and must be corrected. Return the
instrument to Keithley Instruments for repair. See
(on page 8-10).
