Lectrosonics UH190 - Manual (Page 4)

CONTROLS AND FUNCTIONS
The UH190 may be used with a wide variety of microphones. The 3-pin XLR type connector on the UH190 allows
the transmitter to be used with any dynamic microphone, as well as many two wire positive bias lavalier systems
(such as those systems supplied by Lectrosonics).
INPUT JACK
To Mic
Standard 3-pin Switchcraft XLR type. Pin 2 is signal, pin
3 is signal ground, and pin 1 is case ground (see sche­
matic below). The UH190 is self-locking onto a standard
microphone. The XLR connector is permanently bonded
to the metal collar, and is not normally replaceable. The
electret bias is 5 Volts at 1mA or less. The bias is
connected in a “phantom” manner and will not interfere
with any standard balanced microphone. If severe noise
is experienced when the microphone is moved with
1 2
3
+5V
100uf
1uh
1uh
1uh
Preamp
100
respect to the UH190, the cause is an unbalanced
condition between pins 2 and 3 of the microphone.
POWER/MUTE SWITCH
Turns the battery power on and off. The center position is an “audio mute” which should be used when setting the
MIC LEVEL control. The “mute” position disconnects the audio signal from the transmitter and allows you to adjust
the audio modulation level without the possibility of feedback. When turning the transmitter on, pause for a moment
in the “mute” position. This will prevent a turn-on surge from occurring (a “thump” sound).
POWER ON/OFF LED
Glows brightly when battery is good. A weak or dim LED means that the battery is weak, and has about an hour of
operation left. If the LED fails to light, the battery should be replaced. The power LED should light up in both the
“mute” and “on” positions of the POWER/MUTE SWITCH.
The POWER LED is connected to a precision battery test circuit that continuously monitors battery voltage. The
LED is at full brightness with a new 9 Volt alkaline battery. As the battery voltage drops during use, the LED bright­
ness will also decrease. After 7 to 8 hours the battery voltage will be about 7 Volts. The LED will be completely
extinguished. Since the internal circuits are all tightly regulated and the RF output stage has a separate discrete
regulator, the transmitter will continue to operate to a battery voltage of 6.5 Volts. From 6.5 Volts to 6 Volts, the
transmitter will still operate, but with degraded performance. Please note that a weak battery will sometimes light the
POWER LED immediately after turn on, but soon will discharge to the point where the LED will extinguish.
The combination of an accurate battery condition indicator
and regulation of all internal circuits guarantees much longer
battery life, as well as consistent performance versus battery
life.
MODULATION LEDS: Indicate the proper setting of the MIC
LEVEL control.
LEVEL LED: Flickers or glows all the time if the audio volume
is adequate for normal operation.
LIMIT LED: Lights up when the audio volume is high, indicat-
TOP VIEW CONTROL PANEL
ing that the signal level is being limited by the compressor.
Optimum signal-to-noise ratio is obtained when the limit LED
lights occasionally.
MIC LEVEL: Used to adjust the audio input volume for the proper modulation level. Rotate knob until the LEVEL
LED flickers when there is an input signal. The LIMIT LED should light occasionally.
LIMIT LED
LEVEL LED
LEVEL
OFF
MUTE
ON
BATTERY
POWER
LED
4