JBL SP-150, Руководство по обслуживанию, Страница: 11 / 51

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
① check filter pcb ： U5.U6.U7.VR1.VR2 , and parts
related to them
emphasis is to check feedback resistor and
capacitor of OPAMP IC.
② check post - stage ： pin8,9,16,21 of U2 , and
parts related to them
emphasis is to check if U 2 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
Page 10 of 50