No Sound From Speaker Unit - Technics SU-G700E Service Manual

7.12. No Sound from Speaker Unit

No Sound from Speaker Unit.
Confirm the symptom by
changing Speaker Unit.
Is the soldering
condition is okay at speaker lead
wire on Speaker L/R PCB?
Is the connection
okay at fixing the speaker lead
wire on AMP PCB?
Is the correct voltage
presented at P6801 on AMP PCB?
Between Pin 6 and 5: +0.1V or lower
(If the Headphone Insert detection is
activated, the voltage will
be around +3.3V.)
Is FFC between
Main PCB and AMP PCB
Remedy.
Not remedy.
<8>
Replace Speaker L. or R. PCB.
YES
<9>
Fix the speaker lead wire.
YES
Replace Headphone PCB.
YES
NO
damaged?
YES
Replace FFC.
YES
Is the correct voltage
presented at Pin 30 of P6502
on AMP PCB?
Normal: +14.5V
YES
Replace FFC.
Speaker Unit failure
or Speaker Cable Failure.
NO
NO
NO
Replace Main PCB.
Still not remedy.
Is the correct voltage
presented at Pin 1 of P4551
on Main PCB?
Normal: +14.5V
YES
Is the correct voltage
NO
presented at Pin 5 of P6001
on AMP PCB?
Normal: +14.5V
Replace AMP PCB.
29
<8> Speaker lead wire
On Speaker L./R. PCB
<9> Fixing the speaker lead
wire on AMP PCB
NO
Replace FFC.
NO
YES
Replace SMPS PCB.