Marantz SUPERSCOPE BLA-545 Service Data page 6

BLA-545/A-545/BLA-530/A-530
2. Set the distortion analyzer controls for voltge
measurements and apply power to the amplifier.
Set the volume control fully CCW. Set the
SELECTOR switch to PHONO. MIXING volume
control fully CCW (SOURCE).
. If the distortion analyzer indicates more than 1.0 mV
refer to the trouble analysis section of this manual.
. Set the volume control fully CW. If the distortion
analyzer indicates more than 20 mV, refer to the
trouble analysis section of this manual.
MAXIMUM POWER OUTPUT
. Connect the audio oscillator to the AUX input. Set
audio oscillator frequency to 1 kHz. Set SELECTOR
switch to AUX.
. With the distortion analyzer connected across the
output load (8-ohm), set the analyzer on the 30 VAC
scale.
. Turn the analyzer on and increase the audio oscillator
output to 180 mV. The AC VTVM should read 14.1V
AC or more (INCASE BLA-530/A530) (17 V AC or
more INCASE BLA-545/A-545)
E. HARMONIC DISTORTION TEST
1. Set the frequency of the audio oscillator and the
distortion analyzer to 20 kHz.
. Set the controls of the analyzer for voltage measure-
ment on the 30 voit scale.
Adjust the audio oscillator output level until the
analyzer meter indicates 14.1V AC.
(INCASE BLA-530/A530)
(17V AC or more INCASE BLA-545/A-545)
Switch the distortion analyzer to Set Level and
adjust SENSITIVITY for full scale reading on O~0.3%
scale.
. Measure the total harmonic distortion with the
analyzer and verify it is less than 0.1%.
NOTE:
Any parasitic oscillation in the amplifier will be
displayed on the oscilloscope when capacitance is
switched into the load.
6
10.
. Switch the distortion analyzer back to SET LEVEL.
(Do not readjust sensitivity of analyzer.)
. Change the frequency of the audio oscillator and dis-
tortion analyzer to 1 kHz. Adjust audio oscillator
output for a full scale reading on the0 ~0.3% scale.
Measure the distortion, verifying it is no greater than
0.1%.
Repeat steps 7 and 8, changing frequency to 20 Hz.
Distortion should be no more than 0.1%.
Check for parasitic oscillation; there should be none.