SP 150 - JBL Audio Service Manual (repair manual). Page 11

no or lower

no or lower

no or lower

no or lower

SP150/230 Trouble Shooting Flow Chart

 NO

±VCC（±2V）

±19V（±1V）

±12V（±1V）

check R82.R83

check U4.Q1.U1.BD3.T1

①

Check DC 

voltages

②

       NO

POWER

ON

OK

±10V（±1V）

check Q8.Q21.Q22.Q23.R80.R81

check U4 , U5, and parts related to them

emphasis

 is to check capacitors related 

         with U4.U5

③

②

NO

Test Frequency 

OK

OK

④

①check filter pcb：U5.U6.U7.VR1.VR2, and parts
  related to them

emphasis 

is to check feedback resistor and 

         capacitor of OPAMP IC.

②check post-stage： pin8,9,16,21 of U2, and 
                      parts related to them

  emphasis 

is to check if U2 is defective, 

  emphasis 

is to check if 

 is

Q1.C3.D5.D6.D7

          

 defective, 

  and check if R26.R25.C57.C54 is defective

NO

Test 
Sensitivity

OK

check U6-A and parts related to it,
check  -12V voltage（±1V)

NO

NO

check  ±VCC voltage

⑤

Test limiter
circuit

OK

 check if U2 is defective

test method pls 

 refer to above

items

 check limiter circuit

 emphasis

 is to check if U2.C64.C65

          is defective

       

NO

⑥

test power and 
distortion

OK

⑦

① check U2 and C64.C65.L5.L7.C53.C265 related to it,
   see if any part got defective. 
② check all filter capacitors of DC voltage points
    check C3(filter capacitor to GND)

NO

test idle noise

Test DC 

voltages

Response

JBL

150P / 230V Service Manual

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