Installation

VR102 ROOM STATION ADJUSTMENTS
MICROPHONE GAIN
"Microphone gain" is adjusted by means of a miniature trim-pot VR2 located towards the
top of the Room Station PCB.
This pot is normally set to 50% and will rarely require adjustment.
Adjustment will only be necessary on larger systems (15 to 20 stations) where the
accumulated loading effects of all the Room Stations will result in lower communication
levels.
Where adjustment is necessary, use the correct flat bladed screwdriver with a blade width
between 2 and 2.5mm to avoid damaging the pot.
There are no detectable start and stop positions on this pot, which means that it can be
unknowingly rotated past maximum, where it immediately returns back to minimum.
The best way to adjust this pot to the maximum gain position is by measuring its resistance
with an ohmmeter, with power to the system turned off.
The resistance can be measured across the bottom two pins of the pot.
The resistance reading of the pot in the standard 50% position is typically between
2200 and 2300 ohm.
While measuring the two bottom pins of the pot, rotate the pot clockwise until its resistance
reads between 10 and 100 ohm. This position represents maximum microphone gain.
NOTE: Where this pot requires adjustment, the same adjustment is normally done at all
other stations on the system including the Master (where fitted) and the Door
Station.
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