JBL PowerBass PB10, Service Manual

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PB10
23
PB10 Testing Procedure (Revision 1 Only)
A. Power Amp Section
Resistance
Check
Resistance from O/P of the module to GND should be >1M
Ω
(NO LOAD)
Resistance from V+ of the module to V- of the module should read >4k
Ω
Resistance from V+ of the module to O/P of the module should read >1M
Ω
Resistance from V- of the module to O/P of the module should read >1M
Ω
2. Power Up LED RED
With a 5mV signal to Low level input, LED should change to GREEN
-Voltage measurements (DVM)
OP AMP
LED
P-U1(1) P-U1(7)
RED 0Vrms 14VDC
GREEN 12Vrms -14VDC
3. D.C. Operation
-Voltage measurements (DVM) on Power Amp Module
Between +6V V+ O/P V- +15V S/D FR I/P GND -15V
And This
Point
V- GND GND GND GND V- GND GND GND
GND
Get this
Reading
+5.75V +45.7v 0V -45.7V +15.5V +4.75V 0V 0V 0V
-15.5V
4. Check Switching Frequency
•
Oscilloscope - Use scope (EITHER USES AN ISOLATION TRANSFORMER OR
ATTACHES THE PROBE TIP TO SPK- and REFERENCE LEAD TO SPK+)
•
A 10Mv signal may need from the input to trigger the Switch frequency turn on
•
Reading /-10%,1Vpp
B. Pre Amp Section
Low Level Input Sensitivity
-Set up Turn level, Low-Pass Pot Fully CW and LFE switch off
Generator Set at 100mV@50Hz
Signal to Low level input