Line Fuse Replacement; Power-Up Sequence - Keithley 2002 User Manual

Front Panel Operation
WARNING
The power cord supplied with the Model
2002 contains a separate ground wire
for use with grounded outlets. When
proper connections are made, instru-
ment chassis is connected to power line
ground through the ground wire in the
power cord. Failure to use a grounded
outlet may result in personal injury or
death due to electric shock.

2.2.2 Line fuse replacement

A rear panel fuse located below the AC receptacle protects
the power line input of the instrument. If the fuse needs to be
replaced, perform the following steps:
WARNING
Make sure the instrument is disconnect-
ed from the power line and other equip-
ment before replacing the line fuse.
1. With the power off, place the end of a flat-blade screw-
driver into the rear panel LINE FUSE holder. Push in
gently and rotate the fuse carrier one-quarter turn coun-
terclockwise. Release pressure on the holder and its
internal spring will push the fuse carrier out of the
holder.
2. Remove the fuse and replace it with the same type
(0.5A, 250V, slow blow, 5
number is FU-71.
CAUTION
Do not use a fuse with a higher current
rating than specified, or instrument
damage may occur. If the instrument
repeatedly blows fuses, locate and cor-
rect the cause of the trouble before
replacing the fuse. See the optional
Model 2002 Repair Manual for trouble-
shooting information.
3. Install the new fuse and fuse carrier into the holder by
reversing the above procedure.
2-2
20mm). The Keithley part

2.2.3 Power-up sequence

On power-up, the Model 2002 performs self-tests on its
EPROM and RAM, and checksum tests on data stored in
non-volatile memory. (See Table 2-1.) If a failure is detected,
the instrument momentarily displays an error message and
the ERR annunciator turns on. (Messages are listed in Table
2-2.)
If a problem
instrument is under warranty, return it to
Keithley Instruments, Inc. for repair.
If the instrument passes the self-tests, the firmware revision
levels, memory option (if installed), and presently selected
IEEE-488 primary address are displayed. An example of this
display is shown as follows:
Model 2002
Rev. A01 A01 MEM1 IEEE Addr=16
The firmware revision levels (left to right) are for the main
microcontroller and display microcontroller. The revision
level number may be different in your particular unit. If the
MEM1 or MEM2 memory options are not present, that por-
tion of the bottom line is left blank. The IEEE-488 address is
its default value of 16.
Next, if the unit is configured to display the calibration due
date at power-up, the unit shows the following:
Model 2002
Calibration due: mmm/dd/yy
where "mmm" is the month abbreviation, "dd" is the day,
and "yy" is the year. If no calibration date is set, the display
shows that it is due now. (See the Model 2002 Calibration
Manual to set the calibration due date and paragraph 2.12.3
of this manual to set the display option.)
After the power-up sequence, the instrument begins its nor-
mal display, for example:
000.0000 mVDC
Power-up error messages
Error messages that may be displayed during power-up are
summarized in Table 2-2. These are shown when one of the
checksum tests of Table 2-1 fails.
NOTE
develops while the