Operation Manual

09/ 2013 BENNING MM 1 13

- Connect the black safety test lead to the COM-terminal  of the
BENNING MM 1.
- Connect the red safety test lead to the input terminal for V, Ω, µA,  of the
BENNING MM 1.
- Connect the safety test leads across the diodes and read the measured
value on the digital display  of the BENNING MM 1.
- For a typicale silicone diode tested in the forward-based direction a voltage
flow between 0,500 V and 0,900 V is displayed. A display showing"000 V"
indicates a short circuit in the diode, whereas a display showing "1,5 V"
indicates an open circuit in the diode.
- For a diode tested in the reverse-based direction the display reads "1,5 V".
If the diode is damaged, the display will show "000 V" or other values.
see Figure 7: Diode Testing
9. Maintenance

Remove test leads and turn the power off before opening the
BENNING MM 1! Dangerous voltage!
Any work to be carried out on an opened BENNING MM 1 under voltage is
strictly reserved for qualified electrotechnical personnel who must take
special precautionary measures to avoid accidents.
This is how to ensure that the BENNING MM 1 is free from any voltage before
the instrument is opened:
- first remove the safety test leads from measured object.
- then remove both safety test leads from the BENNING MM 1.
- turn the rotary switch  to the "OFF" position.
9.1 Instrument safe-guarding
In certain circumstances, safety during the use of the BENNING MM 1 can no
longer be guaranteed; when for instance:
- there is visible damage to the housing
- measurement errors occur
- the instrument has been subjected to prolonged storage under unfavorable
conditions and
- the instrument has been subjected to severe transport stresses.
In such cases the BENNING MM 1 must be immediately switched off, removed
from the measurement points and secured against any future unintentional
operation.
9.2 Cleaning
Wipe the case of the BENNING MM 1 with a clean dry cloth (exception: spe-
cial cleaning cloths). Do not use any solvents and/or abrasives to clean the
BENNING MM 1.
9.3 Battery replacement

Remove test leads and turn the power off before opening the
BENNING MM 1! Dangerous voltage!
The BENNING MM 1 is powered by two 1.5 V batteries. Battery replacement
(see figure 8 below) becomes necessary when the low battery indicator 
shows in the display .
This is how to change the battery:
- Remove the safety test leads from the measured circuit.
- Remove the safety test leads from the BENNING MM 1.
- Turn the rotary switch  to the "OFF" position.
- Remove the protective rubber holster  from the BENNING MM 1.
- Place the BENNING MM 1 on its front side and remove the screw from the
case back.
- Lift the end of the case back near the input terminals until it gently unsnaps
from the case front at the end nearest to the LCD display .
- Remove the empty batteries from inside the battery holders.
- Insert new batteries correctly into the battery holder.
- Press the case back and case front together again and reinstall the screw.
- Place the BENNING MM 1 back into its protective rubber holster .
see Figure 8: Battery replacement

Please contribute to environmental protection! Batteries should
not be thrown into domestic refuse bins! They can be discarded
at collection points for old batteries or special refuse. Please
contact your municipality for more information.