🔧 Troubleshooting Guide for Audio Kits

🚨 Smoke Appears When Powering On

If smoke appears when turning on the device:

1. Immediately cut the power but try to identify the source before shutting it down.

2. Check the following elements:

   • Poorly cut component leads – Ensure no excessively long leads are touching the chassis or another component.

   • Solder bridges – Check for excess solder causing a short circuit between two pins.

   • Component orientation and polarity – Confirm correct installation, especially for:

     • Diodes
     • Transistors
     • Electrolytic capacitors
     • Integrated circuits

   • Component swaps – Ensure similar components haven’t been mistakenly swapped, particularly:

     • Power transistors
     • Integrated circuits

🔇 No Output Signal

If no sound is coming from the kit, follow these steps:

➡️ Checking Power Supply

Ensure all power supply voltages are correct and meet specifications.

➡️ Checking the “Usual Suspects”

Check the frequent issues listed on our forum:  Sound Skulptor Forum

Exemples of common simple issues to check:

• A forgotten jumper
• Front panel switch in Mute position
  
  

➡️ Checking DC and AC Voltages

The forum provides some images of PCB with marked DC voltage measurement points.
If measured values don’t match expectations, the error is likely in the corresponding circuit stage.

For compressors, expected AC voltage measurements based on settings are also available to help pinpoint faults.

➡️ Tracing the Signal to Locate the signal break

1. Inject a 1 kHz sine wave signal into the circuit input:

   • 100 mV AC for a preamp
   • 2V AC for an equalizer or a compressor

2. Analyse the signal path using the circuit schematic and locate the test points.

3. Measure the signal at each test point with a multimeter set to AC voltage mode.

4. Ensure the signal follows the input amplitude—if adjusting its level, the measured values should change accordingly.

5. Locate the fault – If the signal disappears at a certain point, the issue lies between that point and the previous one.
   
   

🎵 Degraded Output Signal

➡️ Distorted or Bass-Lacking Sound

Check module connection to your monitoring system:

Sound Skulptor modules with an output transformer must be wired in balanced mode.
If one phase is left unconnected, the signal will still be present but altered and lacking low frequencies.

Check the transformers:

Measure winding resistances using specifications available on the forum.

➡️ Crackling or Unwanted Noise

Move the board away from noise sources such as:

• Power transformers
• Switching power supplies
• Light dimmers
• High-current cables
  
  

Check electrolytic capacitors:

Ensure correct polarity.

Inspect solder joints on:

• Connectors
• Potentiometers
• Switches
  
  

Check ceramic capacitors:

A missing or badly soldered ceramic capacitor can cause high-frequency oscillation, resulting in noise at the output.

Locate the noise source:

Lightly tap components with a pencil.
If tapping a component increases the noise, recheck its solder joints.

By following these steps, you can diagnose and resolve most issues with your audio kit. 🎶🔧