JBL ES250P - Troubleshooting Flow Chart; Diagnostic Steps

ES250P Troubleshooting Flow Chart
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Start
Dc voltage check
±Vcc,±15V
O
Check transformer
C
168,C169,D123,
D
124,C170
Power on check
LED red &green
O
Check vol module
& connector
cable& ±15V.etc
Check THD output
power, noise
O
Check pre board
& power board ,
±Vcc,±15V etc
Test frequency
Response
O
Check U102,uR133,
C
121,R135,C122.etc
Test input sensitivity
O
Check U101,R117,
R112,R114 etc
Test protection
O
Check U107.R237
±15Vcc etc
Test limiter circuit
O
Check U106.Q107etc
Auto off Function
Hi pot test
O
Check U103.Q101.
Q102.C131.R142;Ac
cord, Transformer.
O
Listening test
O
The Amp ass’y ok
END
Test phase sw,low
pass sw rabos vr
Check sw103,102,
R158,163,177 etc
12
ES250P