Keithley SourceMeter 3A 2420, Service Manual

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5-6 Disassembly
Front panel disassembly
Use the following procedures to remove the display board and/or the pushbutton switch pad.
1. Unplug the display board ribbon cables.
2. Remove the front panel assembly.
This assembly has four retaining clips that snap onto the chassis over four pem nut studs.
Two retaining clips are located on each side of the front panel. Pull the retaining clips
outward and, at the same time, pull the front panel assembly forward until it separates
from the chassis.
3. Using a thin-bladed screw driver, pry the plastic PC board stop (located at the bottom of
the display board) until the bar separates from the casing. Pull the display board from the
front panel.
4. Remove the switch pad by pulling it from the front panel.
Removing power components
The following procedures to remove the power supply and/or power module require that the
case cover and motherboard be removed, as previously explained.
Power module removal
Perform the following steps to remove the rear panel power module:
1. Remove the analog board.
2. Unplug the cable connecting the power module to the digital board.
3. Disconnect the power module's ground wire. This green and yellow wire connects to a
threaded stud on the chassis with a kep nut.
4. Squeeze the latches on either side of the power module while pushing the module from
the access hole.
WARNING To avoid electrical shock, which could result in injury or death, the ground
wire of the power module must be connected to chassis ground. When in-
stalling the power module, be sure to re-connect the green and yellow
ground wire to the threaded stud on the chassis.