Sony KDS-50A2000 Training Manual page 82

If there is no audio present at the Audio Output Var/Fix jack then the
problem exists in the DSP on the A1-Board. Replace the A1-Board to
repair problem.
If there is audio present at the Audio Output Var/Fix then the DSP circuits
are OK and the problem is located in the Power Amplifier circuit on the
A1-Board or the Speakers.
To isolate the defective component you must check the supply voltages to
the A1-Board and check for defective speakers or damage connections.
The key power supply voltages for the A1-Board are 14V and 11V.
Reference Figure 4-5 for easily accessible test points for these voltages.
If either the 14V or 11V are missing then the problem exists in the power
supply circuits. Replace the G-Board.
Audio 14V Power Supply
Reference Figure3 2-5 & 2-6
Reference Figures 2-5 & 2-6
Speaker Resistance at
CN9800 (or across Speakers)
If both the 14V and 11V are OK, then the next step is to check the speaker
system.
The speakers should measure 8 ohms each.
TVP-23
Check
Audio Output
Var/Fix
Check
Test Point Diagram
Check 11V voltage
Test Point Diagram
Check
& Connections
Measure the speaker
resistance directly on the speaker terminals.
connections to the A1-Board are secure and undamaged. Replace or
repair the system if necessary.
If the speaker system checks OK, then the problem exists on A1-Board.
Replace the A1-Board.
7. Audio Processing System
Confirm all speaker
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