Keithley 2015, Service Manual

Page: 96 / 158

5-8 Disassembly
Front panel disassembly
Use the following procedures to remove the display board and/or the pushbutton switch pad:
NOTE
You must first remove the case cover, the front/rear input switch, and the front input
terminal wires as described earlier in this section.
1. Unplug the display board ribbon cable from connector J1014.
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 transformer and/or power module require that
the case cover and motherboard be removed, as previously explained.
Power transformer removal
Perform the following steps to remove the power transformer:
1. Remove the DMM board.
2. Unplug the transformer wires that attach to the DSP board:
• For TR-332, unplug J1018 and J1020.
• For TR-328, unplug J1019 and J1031.
3. Remove the two nuts that secure the transformer to the bottom of the chassis.
4. Pull the black ground wire off the threaded stud, and remove the power transformer from
the chassis.
Power module removal
Perform the following steps to remove the power module:
1. Remove the DMM board.
2. Unplug connector J1021 from the DSP 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.