Receiver - JBL JSR-400 Service Manual

Dolby Pro-Logic A/V Receiver
Ò
Symptom
FM volume not sufficient.
AM inoperative
Bass control has no effect.
Treble control has no effect.
Auto tune inoperative.
(UP/DOWN)
Manual tune inoperative.
(UP/DOWN)
Memory setting (Keys 1-10)
inoperative.
FL inoperative.
Noisy volume control.
Remote Control Unit inoperative.
Cause and Remedy
A) If volume from both L and R channels is not loud enough: Front end section
defective. "Faulty IC3, Coil T4" Defective C412 on Tuner Board. If sound of one
channel is not loud enough: "Defective Q401, Q402"
A) Damaged IC3 of tuner board. Replace.
B) "Defective T1, T2, T6 or F202 of " Tuner Board. Replace the defective component(s).
C) "Resistors R301, R302 defective." Replace the defecive component(s).
D) "Capacitors C438, C322, C412 defective." Replace the defective capacitor(s).
E) Defective AM switch. Replace.
F) "Defective varicap diodes VC1, VC2." Replace varicap diode(s).
G) Damaged AM loop antenna. Repair or replace.
H) Defective controller circuit component. Replace.
A) Variable resistor BASS defective. Replace.
B) "Defective R60, R63, C47, C48, C52, C53" Replace the defective component(s).
A) Variable resistor TREBLE defective. Replace
B) "Defective R70, R73, R77, R79, " "C58, C61, C63, C64."
Replace the defective component(s).
A) Poor contact on Up/Down key. Repair or replace.
B) Defective IC on Front Board. Replace.
C) Defective tuner circuit components. Replace.
D) "In case of FM only, improper adjustment" of FM front-end. Readjust.
A) Poor contact in Up/Down key. (AM or FM) Replace.
B) Defective IC1 on Front Board. Replace.
A) Poor contact on memory keys 1-10. Replace
B) Poor contact on memory set key. Replace.
C) Defective IC1 on Front Board. Replace the defective component.
A) FL defective. Replace.
B) Defective IC1 on Front Board. Replace.
A) Defective volume control. Replace.
B) "Defective capacitors C1, C2." Replace the defective capacitor(s).
A) Weak battery. Replace.
B) Defective. Replace.
C) Defective IC1 on Front Board. Replace.
JSR-400
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