Crown Macro-Tech MA-5002VZ Service Manual page 36

MA-5002VZ Service Manual
Type of Test
or Adjustment
10. Parallel Mono
11. Current Sense Balance
12. Static Balance
13. Dynamic Balance
5-8 Maintenance
Input Signal and
Load Parameters
1-kHz Sine Wave Note: Always turn power to the amplifier off prior to
No Load changing the position of the Stereo/Mono Switch. With
the dual/mono switch in the parallel mono position,
insert a .775 Vrms 1-kHz signal into channel one. There
should be two signals with the same polarity present,
equal in amplitude, at the outputs of channels one
and two. Both of these signals will be controlled by
the channel one input level control. Switch the stereo/
mono switch to stereo. There should be signal present
only on the channel one output.
No Signal Place the Stereo/Mono switch in the PARALLEL MONO
No Load position. Measure VDC of the channel 1 + output with
respect to the channel 2 + output. Verify null of less
than ±10 mVDC. If necessary adjust null via R2 cur-
rent sense balance pot on the Main Module.
No Signal Place the VZ Mode switches in the VZ-ODEP position
No Load (see Figure 5.4). Measure ±VCC with respect to
ground for channel 1 (P852 & P851 on Control board).
Values should be of equal magnitude and opposite
polarity. If magnitudes vary by more than 500mV, ad-
just static balance pot R568 on the output module for
null (no difference in magnitude). Switch to VZ (AUTO)
position and verify null is maintained. Re-adjust only
if necessary. Repeat check for channel 2 (P854 & P853
on Control board), adjust R568 if necessary.
1-kHz Sine Wave With no load on the amplifier, increase the input to
No Load achieve 125.0 Vrms, ±.3 Vrms, at the output of the
channel under test. Measure TP1/TP2 pin 16 and ad-
just R566 on the output module for 3.500 Vrms, ±.200
Vrms.
Figure 5.2 Bridge MONO
130446-1 Rev. A
Comments
©2000 Crown International, Inc.