Keithley 2000 Repair Manual

Changing trigger link lines
The Model 2000 uses two lines of the Trigger Link rear panel connector as External Trigger
(EXT TRIG) input and Voltmeter Complete (VMC) output. At the factory, line 1 is configured
as VMC and line 2 as EXT TRIG.
NOTE Line 1, 3 or 5 of the Trigger Link can be configured as VMC, while line 2, 4 or 6 can
be configured as EXT TRIG.
Trigger link line configurations are changed by moving the position of resistors inside the
unit. Perform the following steps to change trigger link lines:
WARNING Make sure the instrument is disconnected from the power line and other equipment before
performing the following procedure.
1. Remove the cover from the instrument as explained in “Case Cover Removal”.
The resistors used to select the trigger link lines are located next to the Trigger Link con-
nector as shown in Figure 3-1. The “resistors” are actually solder beads that bridge pc-
board pads. If the factory default lines are selected, the solder beads will be located at
R270 (line 2, EXT TRIG) and R267 (line 1, VMC).
2. To change a trigger link line:
A. Use a soldering iron and solder sucker to remove the appropriate solder bead.
B. Using a solder with OA-based flux, apply a solder bead to the appropriate resistor
location.
3. Replace the cover on the instrument.
Figure 3-1
Trigger link line
connections
Mother Board
(View from top)
Solder Bead
Rear Panel
Trigger
Link
Connector
Trigger Link Lines
Line 1 = VMC (R267)
Line 2 = EXT TRIG (R270)
Line 3 = VMC (R266)
Line 4 = EXT TRIG (R268)
Line 5 = VMC (R265)
Line 6 = EXT TRIG (R269)
R270
R269
R268
R267
R265
R266
(Factory Default Configured)
3-6 Routine Maintenance

Keithley 2000 Specifications

General

Digits	6.5
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Resistance Range	100 Ω to 100 MΩ
Connectivity	IEEE-488 (GPIB)
Display Type	VFD