Adjustments; Wru-806A Tuner Unit Adjustment - Sony MB-806A Service Manual

3-2. Adjustments

This section describes the following adjustments (and
checks) required to satisfy the specifications.
Adjustment Item
3-2-1.

WRU-806A Tuner Unit Adjustment

1. Muting level and RF level adjustment
2. Output level adjustment
3. Noise squelch adjustment
3-2-2. Overall Characteristic Check
1. Output level check
2. S/N check
3. Frequency characteristic check
4. Distortion ratio check
5. RF level indicator check
6. AF level indicator/AF indicator check
7. Muting level/RF indicator check
8. BATT indicator check
9. Tone squelch check
10. DC +9 V OUT voltage check
n
= _113 dBm
0 dBuV
EMF
(EMF = Electromotive force)
0 dBm = 1 mW at 50 Z loaded
3-2
Note on Adjustment
The RF level of the input signal (the output level of the
signal generator) for adjustment is expressed as an open
ended voltage in unit dBu (0 dBu = 1 uV).
The adjustment is to be performed by calibrating the output
level of the signal generator
as shown below.
Calibration method
(1) Connect the RF millivoltmeter to the signal generator
as shown in the figure below.
(2) Adjust the level of the output signal from the signal
generator (SSG) so that the RF millivoltmeter reads
50 mV. The level of the output signal from the signal
generator (SSG) when RF millivoltmeter reads 50 mV
shall be specified as 100 dBu (at no load).
50 Z
termination probe
RF millivoltmeter
(set in 100 mV range)
Signal generator
(SSG)
100 dBu
50 Z
OSC 50 Z
Adjust the output of
the signal generator
(SSG) so that the
meter reads 50 mV.
V 50 mV
MB-806A (CE)
WRU-806A (CE, AU)