JBL PowerBass PB10 Service Manual page 24

PB10
PB10 Testing Procedure (Cont.) (Revision 1 Only)
- Voltage measurements
U1(7) U2(7)
180mV 266mV
2. High Level Input Sensitivity
-Set up
-Voltage measurements 15.3V at speaker output
3. Low-Pass
-Set up Set Generator at 100 mV@100Hz
Signal to Low level input
Measure voltage at speaker output
-Voltage measurement
Low-Pass Pot Setting
CW
CCW
4. LFE
-Set up Set Generator at 100mV@200Hz
Signal to Low level input
Measure voltage at speaker output
LFE switch Setting
OFF
ON
See flow chart next page for diagnostics.
OP AMP
U1(1) U2(1) U1(14)
325mV 404mV 451mV
Turn level, Lo Pass Pot Fully CW and LFE switch off
Set Generator at 1.09V@50Hz
Signal to High level input
Output
11.4V
2.19V
Output
2.96V
8.40V
U2(14) U2(8) PU1(14) PU1(8)
451mV 1.33V 6.37V
24
SPEAKER
O/P
5.72V 15.3V