AEMC 6471 User Manual page 73

• Fuse for clamp terminal ES (Xv):
If this fuse is defective, the unit will no longer recognize a clamp that is connected
to terminal ES (Xv), making it impossible to perform a 4-Pole earth measurement
with a clamp or an earth measurement with 2 clamps.
To test this fuse, select the 4-Pole measurement function and connect a test clamp
to terminal ES (Xv). If a clamp symbol does not appear next to the symbol for ter-
minal ES (Xv) in the display, the fuse must be replaced.
NOTE: For safety reasons this fuse must always be replaced by an identical
model: 0.63 A F 250V 5x20mm 1.5kA (Cat. #2135.81)
Procedure for replacing fuses:
1. Disconnect the unit completely, turn the rotary switch to OFF, and close
the lid.
2. Loosen the four permanent screws at the bottom of the unit, but do not
remove them.
3. Open the lid and carefully turn the housing upside-down, making sure the
front panel does not fall out. Then carefully pull the front panel and the unit
all the way out of the housing.
4. The fuse for terminal H (Z) is accessible at the back of the unit (in the
corner near the terminal for the battery charger).
5. If only the fuse for terminal H (Z) needs to be replaced, jump ahead to step
13. To replace the fuse for the clamp terminal ES (Xv), continue on.
6. Loosen the two screws on the lid of the battery case and remove the lid.
7. Pull the battery a short way out of the case without overstretching the con-
nection leads, and loosen the two screws at the bottom of the case. Then
put the battery back into the case.
8. Making sure the battery leads are not overstretched and that the battery
does not fall out, carefully lift off the back of the unit, turn it over and place
it next to the front panel with the electronic components.
9. The fuse for the clamp terminal ES (Xv) is now accessible on the printed
circuit board [in the corner near terminal E (X)]. When replacing the fuse,
avoid touching the circuitry or components.
10. Return the back of the unit to the front panel with the components, taking
care not to stretch the battery leads. Carefully lower the back of the unit
and make sure that it is aligned correctly (the four cylindrical holes on the
back must slip over the four mounting pins on the front panel). Also make
sure you do not pinch the battery leads or other wires or components.
Ground Resistance Tester Model 6471
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