BNC 6040 - Manual (Page 17)

17
OPERATING INFORMATION
TROUBLESHOOTING
To start, make sure that the line cord is plugged in all the way, and that the power-on key switch is in
the ON position. Verify that the 115 V/230 V selection switch is properly set for your area. (If it is not,
unplug the line cord and move the switch. Make sure the proper fuse in in place before plugging the
cord back in.)
With the line cord unplugged check the fuse. Make sure that it has not blown and that it is of the correct
value for the line voltage being used.
When ac power is applied, you should be able to hear the fan. The unit will not operate properly if the
side vents are blocked.
A thermal cutoff switch will shut off the power to everything but the fan should the temperature exceed
50
o
C. Power will be restored when the unit has cooled sufficiently. Make sure that the fan and the side
vents are not blocked, and that the fan is operating properly.
With the power off, make sure that the module is seated correctly in the mainframe.
LCD Contrast
If there are no characters on the LCD or the contrast is poor, a simple internal adjustment may solve
the problem (see the calibration procedure for details).
Cold Boot
If the instrument turns on, but is completely unresponsive to the keyboard or displays the error
message "Invalid Function." then the module's memory may have been corrupted causing the
instrument to "hang up." To correct for this, turn the unit off, then hold down the ENTER key and turn
the power back on. This will initialize the module's memory to its default settings (see the module's
manual for the specific values).
Quick Test
Since the 6040 uses a modular approach, operating problems can arise from either the mainframe unit
or the installed module: the problem must be localized to one or the other. To test the mainframe, turn
the power off, remove the module, and switch the power back on. Press the TRIG key until the internal
trigger parameter is displayed ("Trig Int: 1.000
kHz"). Press the 11} key, the {10
x
} key, the {5} key, and the ENTER key in sequence. The display will
read "Trg Int: 100.0 kHz."
Connect the TRIG OUT and PULSE OUT to channels A and B of an oscilloscope. Trigger the
oscilloscope on the leading edge of TRIG OUT. Set the oscilloscope for 1 us per division. Display the
PULSE OUT. A pulse of +5 V amplitude and 1 us duration should occur 1 µs into the sweep.