Read JBL E 250P (serv.man15) Service Manual online
E250P
Testing Procedure
- 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
306.9mV
461mV
460mV
658mV
628mV
598mV
2.326V
2.02V
3.57V
23.33V
2. High Level Input Sensitivity
-Set up
Turn level, X’OVER FREQ POT Fully CW and LFE switch off
Set Generator at 1.3V@50Hz
Signal to High level input
-Voltage measurements 15.3V at speaker output
3. Low-Pass
-Set up
Set Generator at 200 mV@100Hz
Signal to
Line
level input
Measure voltage at S+ speaker output
-Voltage measurement
X’OVER FREQ. Setting
Output
CW
14.03V
CCW
4.8V
4. LFE
-Set up
Set Generator at 200mV@200Hz
Signal to
Line
level input
Measure voltage at S+ speaker output
LFE switch Setting
Output
Normal
6V
LFE
18.32V
See flow chart next page for diagnostics.
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