Tech Bulletin: Troubleshooting Symphony I/O Ribbon cables

Overview This Tech Bulletin shows you how to resolve issues that may occur due to an improperly installed or faulty internal 64-pin I/O Module ribbon cable.   Reported Symptoms When an I/O Module ribbon cable has become defective, users report one or more of the following symptoms: 

    • Random “spikes” observed on the front panel meters or on Maestro Input meters.
    • Clicks, pops or distortion present in the audio signal even when the audio software buffer is set high.
    • The audio signal becomes distorted over time.

Testing the IO Module Ribbon Cable To test the IO Module ribbon cable, follow these steps. DO NOT PERFORM THIS TEST with A 16 x 16 Analog Input/Analog Output module, damage to the I/O Module may result.

    1. Unplug the AC cable and remove Symphony I/O’s top panel.
    2. Re-seat both ends of the 64-pin ribbon cable (location shown below).Symphony Module Ribbon Cable Location
    3. Re-connect the AC cable, then connect Symphony I/O’s USB port to a Mac. Power the unit on.
    4. Press and hold the right encoder to set Symphony I/O to USB audio interface mode. Open Maestro,click on the Input tab and adjust the window to see all meters.
    5. Lightly manipulate the 64-pin ribbon cable that connects the I/O Module to the Main board, looking for spurious meter spikes on the front panel and in Maestro. If two I/O Modules are installed, test each cable.
    6. If any spurious signals are observed, replace the ribbon cable with an Apogee-approved cable.
    7. Please see the Apogee Tech Bulletin video entitled “Symphony I/O Ribbon Cable Troubleshooting” below for an example of a faulty ribbon cable.

Symphony ribbon cables since 2013 are Grey in color. If you have a Black colored module ribbon cable, it is more likely to be faulty and should be replaced.