Operation - Tait TM8200 Accessories Manual

18.2

Operation

18.2.1 TOP / TM8000 switch
18.2.2 TOP Mod Audio / Off / Mic Audio switch
18.2.3 Hook On / Hook Off switch
TM8100/TM8200 Accessories Manual
© Tait Electronics Limited August 2005
This section explains the function of the TOPA-SV-024 test unit controls.
The procedure for using the test unit is described in the section of the
service manual covering test equipment.
This 2-way toggle switch is used to switch attenuation resistors (R4, R5, R6)
in and out of the line from the radio's positive speaker output to the positive
receive audio/SINAD output of the test unit (before the isolating transformer).
When set to TOP, the attenuation resistors are switched out.
When set to TM8000, the attenuation resistors are switched in
(attenuation 10:1).
Important
Selecting the wrong switch position can result in incorrect
SINAD readings.
This 3-way toggle switch is used to switch between Mod Audio (Tait Orca
portables only), Mic Audio, and Off (no audio signal).
With the Tait Orca portables, this switch can be used for setting up dual
point modulation by applying modulation to different parts of the radio.
For normal transmit deviation tests (Tait Orca portables and TM8000),
this switch is set to Mic Audio.
Important
When using the test unit with Tait Orca portables, the
Hook On / Hook Off toggle switch must be set to
Hook Off. Tait Orca portables do not have a hookswitch,
and if the switch is set to Hook On, the Tait Orca portable
F1 function is activated.
This 2-way toggle switch is used to simulate the microphone hookswitch
opening ("hook off") and closing ("hook on"). This is done by switching a
12kΩ resistor (R3) in or out of the MIC_PTT line.
When set to Hook Off, the 12kΩ resistor (R3) is switched out of the
MIC_PTT line. This simulates the microphone being removed from the
microphone clip.
When set to Hook On, a 12kΩ resistor (R3) is switched into the
MIC_PTT line. This simulates the microphone being placed on the
microphone clip.
TOPA-SV-024 Test Unit 135