JBL PowerBass PB10, Service Manual

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PB10
27
PB10 Testing Procedure (Cont.) (Revision 2 Only)
- Voltage measurements
OP AMP
U2(1) U2(14) U2(8) U3(7) U3(1) U3(14) U3(8) U5(7) U5(1)
SPEAKER
O/P
133.6mV 200.2mV 245.9mV 314.8mV 314.9mV 350mV 1.67V 1.452V 2.098V 15.3V
2. High Level Input Sensitivity
-Set up Turn level, X’OVER FREQ POT Fully CW and LFE switch off
Set Generator at 1.15V@50Hz
Signal to High level input
-Voltage measurements 15.3V at speaker output
3. Low-Pass
-Set up Set Generator at 100 mV@100Hz
Signal to
Line
level input
Measure voltage at S+ speaker output
-Voltage measurement
X’OVER FREQ. Setting Output
CW 10.72V
CCW 2.165V
4. LFE
-Set up Set Generator at 100mV@200Hz
Signal to
Line
level input
Measure voltage at S+ speaker output
LFE switch Setting Output
Normal 2.9V
LFE 7.62V
See flow chart next page for diagnostics.