No Power Supply:
First, check if the power cable is properly connected to the power source and the fuse. Inspect the power cable for any damage or breaks. Also, check if the fuse is blown or has poor contact. If the fuse is faulty, replace it. Next, examine the rectifier bridge or electrolytic components in the power amplifier’s power supply section, such as diodes or bridge stacks. Look for any damaged or burnt parts. Additionally, inspect other related components like the power amplifier tubes for faults.
Signal Indicator Works but No Sound Output:
Start by checking if the speaker is functioning properly. If the speaker is fine, test the speaker leads for good contact and ensure the terminals are secure. Open the case and visually inspect the components or listen for the output relay to engage. If the relay doesn't activate, check if the contacts are oxidized or burned. In that case, replace the relay. If you have a multimeter, measure the resistance between the input and output of the relay to confirm its functionality.
Power Light On, No Sound, But Relay Is Activated:
Use a multimeter to check if the power supply to the amplifier is stable. If the power is normal, test the signal input by touching the input terminal with your hand. If you hear a loud hum or current, the power amplification stage is likely working. Check the signal cables for poor connections or damage. If there's an issue, use the multimeter to locate and fix the faulty wiring.
No Sound from Amplifier Output:
Ensure the speaker unit is working correctly. Check the speaker terminals for burn marks or poor contact. If the terminals are blackened, clean them and tighten the screws to restore proper connection.
Boot Protection Light Is On:
First, use a multimeter to check if the speaker coil is shorted or if the resistance has dropped (normal resistance should be at least 30 Ω). If the external line resistance is normal, the problem may lie within the power amplifier itself. Check the power supply and internal components for faults.
Unstable Volume Level:
1. Poor connection in the signal cable;
2. Faulty potentiometer contacts;
3. Damaged coupling capacitor;
4. Poor contact in the feedback resistor.
No Sound When Motherboard Is Normal:
1. Signal cable not connected or coupling capacitor open;
2. No power supply on the front panel – check the power supply section;
3. Faulty volume control potentiometer;
4. Faulty operational amplifier IC.
Distorted Sound from Pure Power Amplifier:
1. Soft breakdown of the power tube;
2. Low or no voltage between positive and negative rails;
3. Faulty resistance value or component.
Level Indicator Not Working:
1. Check if the voltage is within the correct range;
2. Confirm that the signal is being sent to the amplifier;
3. Test the components for damage or failure.
Treble and Bass Controls Not Working:
1. Is the potentiometer working properly?
2. Check if the voltage is stable;
3. Test the RC components for faults;
4. Ensure all wiring is properly connected and free from poor contact;
5. Inspect solder joints for cold or false soldering.
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