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Checking of recording level
Measuring
VTVM
instrument
Self-recording/playback
Mode
1 kHz/-8dBs
Input signal
Test point
Audio output terminal
Control
- 8 2 3dBs
Specification
1. Feed 1 kHz, -8 dBs signal to the audio input
terminal. Make self-recording and playback of
the signal.
2. Make sure the output at the audio output
terminal is - 8 f 3 dBs.
3. If out of spec, readjust the playback level and the
Adjustment of the RF AGC
Oscilloscope
Measuring
instrument
Signal generator
EE
Mode
Colour bar signal
Input signal
Test point
Pin @ of IF Pack (Video Output)
Adjusting point VROOl (AGC control)
1. Receive the colour bar signal (input field
strength: 80 dBu).
2. Observe the video output terminal waveform on
the oscilloscope. Adjust VROOI (AGC control) in
the IF pack until the noise disappears from the
oscilloscope screen and the waveform nearly
comes into sync.
Figure 2-15.
Adjustment of the AFT
Input signal
Colour bar signal (70 dBu)
Test point
Pin @ of IF Pack (Video Output)
Adjusting point
TOO2 (AFT coil)
Specification
1.
Receive the colour bar signal (input field
strength: 70 dell).
2.
U s i n g t h e s i g n a l g e n e r a t o r , f e e d t h e PIF
frequency (36.87SMHz) signal (sinewave) to the
tuner IF output terminal.
3.
Set the tuning switch to the VHF or UHF position.
Keep the tuning button (+) or ( - ) depressed
until the beating on the oscilloscope screen be
m i n i m u m . .
4.
Set the tuning switch on the normal position.
Adjust TOO2 (AFT coil) so that beating on the
oscilloscope screen be minimum.
RF AGC
41
AFT
IF Pack
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