TROUBLESHOOTING
6-1
Nothing Happens At Turn On
Make sure that the power entry module on the rear panel is set for the ac line
voltage for your region, that the correct fuse is installed, and that the line cord
is inserted all the way into the power entry module. The selected line voltage
may be seen through the clear window, just below the fuse.
When the unit is plugged in and turned "ON", the unit's firmware version
number and serial number will be briefly displayed. Then the self tests should
execute.
Reset
If the unit displays no sensible message, the "cold boot" procedure may fix
the problem. To reset the instrument, turn the unit off. Then, while holding the
backspace key ([<-]), turn the unit "ON". This procedure initializes the RAM
and recalls the factory calibration values. See 3-5.
Internal Fuse
If the unit powers on correctly but makes unstable or wildly inaccurate
readings, the internal fuse may be blown. This can also cause the unit to fail
the Self Test (Out Err3). To change this fuse, the top of the unit must be
removed. To do this, first turn off and unplug the unit. Next remove the four
screws located on the bottom at the corners of the unit. Place the unit right
side up on its feet and gently slide the plastic top off of the metal base. It is
necessary to slide the top gradually off of the fixture and the back panel,
since it fits tightly over these. When the top is removed, stand it on it's left
side near the unit to avoid damaging the front panel cables. The internal fuse
is located near the fixture, on the right hand side of the unit. Remove the old
fuse and inspect it for damage. It isn't always possible to see the damage so
measure it with an ohmmeter. If it is damaged, replace it with a 2AG 1/4 A
fuse. Replace the top, taking care to align it over the fixture and rear panel.
Finally replace the four screws and verify that this fixed the unit.
External Bias Fuse
If the unit makes unstable or wildly inaccurate readings when an external bias
is applied, the external bias fuse may be blown. To change it, power off and
unplug the unit. Use a screw driver to remove the fuse holder and the fuse
from the rear panel. It isn't always possible to see the damage to a fuse, so it
can be helpful to measure it with an ohmmeter. If it is damaged, replace it
with a 3AG 1/4 A fuse. Replace the fuseholder and fuse and verify that the
unit operates correctly.