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Meyer Sound Documentation

System Verification Process
In this section:
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The verification process uses only the ohm (Ω) setting of your meter. An “open” refers to a reading as if the probes are not touching anything. A “short” refers to a reading as if your two probes are touching together (the meter should read 0 Ω but technically there is resistance in your probes and the reading is more like 0.2 Ω).

Note

All measurements are approximate due to component variances, different cable lengths, and other factors.

Caution

AC power to the MPS-488HP/MPS-482HP should be disconnected during the verification process.

Step 2 — Verify the Loudspeaker Input
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Note

  • Electronic circuitry is involved in these measurements. One or more capacitors will be affecting your readings. The capacitor causes the reading to slowly rise as the capacitor charges from the meter. This process takes about 30 seconds or less. The important measurement is when the value stops rising.

  • Examples of input modules are provided on page 2 of this document for reference.

Procedure. To check the input module on the loudspeaker, unplug the cable from the loudspeaker and measure at the input between:

  1. Audio (+) and Audio (-)

    You should see 21 kΩ.

  2. Audio shield to each of the Audio Pins. Please allow capacitors to charge up.

    You should see 55 kΩ.

  3. 48 VDC (-) and Audio shield.

    You should see 1 kΩ or less.

    Caution

    If you measure larger values than indicated in the above steps, the input has likely been damaged by incorrect wiring. Contact the Meyer Sound Service department for further instructions.

Step 3 — Verify the Cable
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  1. Unplug both the power supply and the loudspeaker.

  2. At the power supply side and following the table shown in the figure below, keep one of your probes on the first pin and measure to each of the other pins. Next, move the stationary probe to pin 2 and measure to the other pins as shown. You should not see a short between any of these pins.

    VerifyingCableTable.ai

    Pin Measuring Order

    VerifyingPinsWires.png
    VerifyingPinsConnector.png

    Phoenix Connector Pinout (left) and EN3 Connector Pinout (right)

    Note

    The same measurements must be taken on the loudspeaker end.

    Caution

    Pay close attention to the polarity of both the audio pins and the voltage pins. The positive 48 V DC pin, pictured in red in the figure above (left), must go to pin 2 only to avoid damaging your sound system.

    Pin 1 (48 VDC (-)) and Pin 3 (audio shield wire)

Step 4 — Verify the Loudspeaker Input Through the Cable
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To verify the loudspeaker through the cable, plug the cable into the loudspeaker, and measure the cable at the power supply side (see Step 3—Verifying the Cable for the connector pinouts).

Note

If the cable has been wired incorrectly, the measurement will be a random number or a negative number.

Procedure. Measure the cable between:

  1. Pin 4 (white wire) and Pin 5 (blue wire)

    The measurement reading should be approximately 21 kΩ.

  2. Pin 3 (audio shield wire) and Pin 4 (blue wire)

    The measurement reading should be approximately 55 kΩ.

  3. Pin 3 (audio shield wire) and Pin 5 (blue wire)

    The measurement reading should be approximately 55 kΩ.

  4. Pin 1 (48 VDC (-)) and Pin 3 (audio shield wire)

    You should see 1 kΩ or less.