Help! My Scan-A-Line system quit working

Help! My Scan-A-Line System has quit working

When a working Scan-A-Line system quits working there is a better than even chance that you have a damaged cable or connector. The sequence of tests that needs to be performed is important so that more damage to the system doesn’t result from your the attempts to repair it.

    1. Look for proper power supply outputs. Most Scan-A-Line systems use LED indicators to show proper power supply operation. Generally there will be an indicator for +12V,-12V and on some systems a +5V indicator as well. These indicators are generally visible when the enclosure door is opened and line power is supplied. If you have a digital voltmeter you can verify the proper voltage levels. Grey wires are circuit ground. Measure from one of the Grey wires to a solid Red wire to measure the +12Volt buss. The -12Volt lines are solid Black and the +5Volt lines are Red & White striped. Actual voltages should be within 0.5Volts in most cases. If one of the Voltage indicators does not light or lights only very dimly, this indicates a possible short circuit in the system.
    2. To locate an external short circuit, try removing all of the cable connectors from the processing unit. When cables are not connected does the voltage indicator return to normal? If this restores proper voltages then try connecting one cable at a time until one of the indicators does not light or is again very dim. The offending cable or the module or sensor connected to it will have a short circuit.
    3. Try disconnecting the remote end of this cable from the Sensor or module it is connected to. If this doesn’t restore power there is a problem in the module or Sensor you just disconnected. It is best to return the defective Sensor or Module for factory repairs. Please call Harris Instrument for a Return Authorization.
    4. If the problem appears to be in the cable you can verify cable integrity with an Ohmmeter continuity test. Scan-A-Line cables are usually Male to Female. Pin(a) male should be connected to Pin(a) female and so forth. There should never be a cross connection between (a) and any other connection terminal and so forth. Examine your cable for a deformed cross section that could indicate that it has been crushed. This sort of damage may test OK until the cable is twisted or bent. Because damaged cables and cable connectors cause at least 50% of Scan-A-Line failures, it pays to have spare cables on standby to keep your system in operation.
    5. WARNING! Under no conditions should you substitute spare Receivers, Emitters or Processing units before these trouble shooting steps have been taken. Plugging a good module into a shorted cable usually causes damage to the spare module thus making it impossible to repair your system without help from field service.
    6. Other possible causes of system failure are improper receiver alignment or interference from an external light source, especially strobe lights. Pay special attention to any new lighting source that may be modulated at a high frequency. Poor grounding on line transportation drive and synchronizing controllers can also cause interference. Is there any part of the system that seems to cause the problem? Shut down systems one at a time to see which might be a problem. The important question to answer is “What could have changed since the system last worked properly?” Use this blog to describe your problem or give us a call at 740-369-3580.

      By sharing our problems and solutions we can build a strong Scan-A-Line Community with this blog. Please comment or contribute to help get this effort underway.

      Many Thanks,

      Dave Harris

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