DSP-15 User Manual
Page 20 of 23
DSP15_MAN_C
6. Troubleshooting
No Power LED
The first step is to insure that the correct model of the detector is being used for the installation. Insure that the
wiring is correct, and the correct voltage is being used.
Use a meter to measure the voltage applied to the detector. For the LV version the voltage must be above
10.25V AC or DC. For the 117 version the voltage must be above 100V AC. For the 230 version the voltage must
be above 200V AC.
If the correct voltage is applied and the power LED is not on, replace the detector.
Power LED Flashes On Once Every 2 Seconds
The first step is to insure that the correct model of the detector is being used for the installation. Insure that the
wiring is correct, and the correct voltage is being used.
Use a meter to measure the voltage applied to the detector. For the LV version the voltage must be above
10.25V AC or DC. For the 117 version the voltage must be above 100V AC. For the 230 version the voltage must
be above 200V AC.
If the correct voltage is applied and the power LED is still flashing, replace the detector.
Power LED Flashes Slowly (1 Hz)
This flash rate indicates that the detector has an open loop, a high resistance in the loop circuit, or excessive
inductance.
The first step is to confirm that the detector has a loop connected to it and the loop is connected to the correct
pins (see the wiring configuration for the pin out).
If a loop is connected to the correct pins of the detector, disconnect the loop and using an ohmmeter, check the
resistance of the loop circuit. If the resistance is above 5 ohms there is a bad connection or the wire has been
damaged. The resistance will typically be 1.5 ohms or less.
If the resistance is below 5 ohms, the loop inductance should be checked. This is done using an inductance
meter. The inductance of the loop should be less than 1500 microhenries. It is very unusual to have a loop with
an inductance value this high, but it is possible with very large loops and many turns. If the loop inductance
value is above 1500 microhenries, the loop will have to be replaced with a loop with less inductance. Contact
technical support for help with very large loops.
If you do not have a meter capable of measuring resistance and inductance but do have another operating
detector in the same box, you can skip to this step. Swap the loops between a working detector and a failing
detector. If the problem follows the loop the loop is the problem. If it stays in the same detector, replace the
detector.
