Studio Technologies Gen II - Manual (Page 15)

Generation II User Guide Issue 3, July 1991
Studio Technologies, Inc. Page 17
2) With the DC voltmeter common lead
connected to test point COM: check test
point COMP for 1.35±0.5Vdc. If not
within this range, set R85 to give
1.35Vdc at test point COMP.
3) With DC voltmeter common lead con-
nected to test point COM: check test
point EXP for 1.35±0.5Vdc. If not within
this range, set R88 to give 1.35Vdc at
test point EXP.
BBD Clock Frequency
1) Connect common lead of frequency
counter to test point COM. Check test
point CLK for 64±2kHz. Remember, you
must have the unit in the music mode. If
not within this range, set R63 to give
64±2kHz.
Incoming Audio Test Signal
1) Connect the AC voltmeter common
lead to test point COM.
2) Adjust the audio generator output level
to give a
–
10dBu reading at test point
AUDIO 1.
Compressor
1) Move the AC voltmeter lead to test
point AUDIO 2. Note the reading that
you observe. It should be
–
10±2dBu.
2) Reduce the generator level by 20dB.
3) Observe the level at AUDIO 2. It should
have dropped 15±0.3dB. If not, adjust
R85 to get this condition.
4) Raise the generator level 20dB. Ob-
serve level at AUDIO 2.
5) Reduce the generator level 20dB.
Observe level at AUDIO 2. It should
drop 15±0.3dB. If not, again adjust R85
to get this condition.
BBD Distortion
1) Set the audio generator’s frequency to
5kHz; adjust its level to give
–
10dBu
when measured at test point AUDIO 1.
2) Set the front panel stereo intensity
control to give
–
10dBu when measured
at test point AUDIO 3.
3) Connect distortion analyzer to measure
at test point AUDIO 3.
4) Adjust R13 to give minimum distortion
(THD + Noise). The acceptable mini-
mum distortion is 0.35 percent or lower.
The usual minimum is 0.10 to 0.25
percent.
Expander
1) Set generator frequency to 1kHz; adjust
its level to give
–
10dBu at test point
AUDIO 1.
2) Measure level at AUDIO 3. You should
have left the front panel stereo intensity
control where it was set a few steps
previously.
3) Reduce the generator level 20dB. Level
at AUDIO 3 should drop 20±0.3dB. If
not, adjust R88 to get this condition.
4) Raise generator level 20dB. Observe
level at AUDIO 3.
5) Drop generator level 20dB. Observe
level at AUDIO 3. It should drop
20±0.3dB. If not, again adjust R88 to
get this condition.