Replacing The Lcd - Fluke 77 Calibration Information Manual

Cleaning
To avoid electrical shock:
•
Remove test leads and any input signals before cleaning.
•
Do not reinstall the pca until it is completely dry.
•
Dirt or moisture in the terminals can affect readings.
To avoid damaging the Meter, do not use aromatic hydrocarbons or chlorinated
solvents for cleaning. These solutions will react with the plastics used in the
instruments.
Do not use detergents of any kind for cleaning the pca.
Clean the instrument case with a damp cloth and mild detergent.
The pca may be washed with isopropyl alcohol or hot deionized water and a soft brush. Remove excess
cleaning material with clean dry air at low pressure, then dry the pca at 50 °C.

Replacing the LCD

To prevent contamination, do not handle the conductive edges of the LCD or
the LCD Elastomeric Connectors.
If the edges are contaminated, clean them with alcohol. Allow the alcohol to dry
before reassembling.
To remove and replace the LCD, perform the following procedure (refer to Figure 3):
1. Turn the rotary switch to
2. Remove the four screws from the case bottom, and separate the case top from the case bottom
The circuit board remains attached to the case bottom.
3. Remove the battery compartment and disconnect the battery from the battery connector.
4. Remove the pca screw located under the 440 mA fuse, and lift the pca out of the case bottom. The
beeper is loose in the case. Exercise caution not to damage it.
5. Loosen the four screws in the area of the LCD on the back of the pca. This will facilitate reinstalling
the LCD.
6. Insert a small, flat-head screwdriver under the LCD mask edge and gently pry the LCD mask from the
snaps.
Take care to not break the LCD with the screwdriver.
7. Lift out the LCD.
8. Make sure that all connector contact points are clean. Refer to "Cleaning" for more information.
9. Install a new LCD, taking care that it is correctly oriented.
10. Reattach the LCD Mask to the LCD assembly by snapping the LCD mask into place.
11. Tighten the 4 screws on the back of the pca.
12. Lay the pca back into the case bottom, and screw it down.
13. Reinsert the 440 mA Fuse.
14. Reinstall the battery.
15. Rejoin the case bottom, case top, battery compartment door, and reinstall the four case screws.
XWWarning
W Caution
W Caution
and remove the test leads from the Meter terminals.
OFF
W Caution
Digital Multimeter
Cleaning
9