4.4
DISASSEMBLY FOR MODEL 871A AND MODEL 872A
The PC board and LCD assembly are not secured once the case retaining
screws are removed. Be careful not to allow the PC board and LCD
assembly to fall out or shift out of position.
1. Place the unit face down on a bench or other similar surface and
remove the battery compartment cover. Remove and disconnect the
battery. Remove the two #4-40 x 7/8 retaining screws.
2. Grasp the bottom cover at the input jack end and with a lifting
and forward pushing motion (see Figure 4-4 and Figure 4-5), carefully
remove the bottom cover. While removing the cover, feed the
battery connector through the access hole in bottom of the
battery compartment.
3. The component side of the PC board is now exposed and the battery
can be reconnected for troubleshooting. To read the display, some light
downward pressure at the top end of the circuit board may be required
in order to make contact through the conductive elastomer strip,
between the circuit board and the LCD.
4. To remove the PC board from the top cover, grasp the TC switch
assembly and lift until the input jacks become disengaged from the
cover. The PC board can now be removed using a slight clockwise
motion to free the two switch knobs from their normal positions in
the case.
5. The LCD assembly will remain in the top cover when the PC board is
removed. Again, be careful not to allow the LCD assembly to fall
out accidentally.
6. The two switch knobs can be removed from the PC board assembly by
simply pulling them off the switch shafts.
7. The LCD assembly, along with the strip connector, lifts out of the case.
8. To reassemble the unit, reverse the above procedure.
NOTE
Proper alignment of the strip connector is necessary when reinstalling the
LCD assembly. Make sure that the conductor side of the strip connector is
positioned against the plastic support of the assembly.
WARNING
Be sure to replace the on-off switch cover. Common-mode
voltage will be present on the switch, creating a possible hazard if
the cover is not replaced
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