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TekTip: Troubleshooting "Phantom Calls"

The term "Phantom Call" refers to a system that is annunciating a call, but no specific room has placed a call. This problem is typically caused by current leakage from a patient station or and emergency station. Lightning damage, moisture corrosion, ESD, and component degradation due to age are typical causes of current leakage.

The first step to troubleshoot this problem is to determine which common line is showing signs of current leakage. Remove the "R" Common Line from the PK151N Control Unit. Insert a current meter in series with this line by putting one probe on the "R" Terminal on the PK151N, and the other probe on the "R" Common Line. The system should have no calls placed when this test is made. If any current is passing, with no calls placed, then one or a group of patient stations are leaking current. The next step is to perform the above test at a patient station to determine if any current is passing through the unit. A unit with no call placed should read zero current draw, and if the unit reads otherwise, it should be repaired/replaced. This troubleshooting process should also be repeated on the emergency call common line "Q" and bath stations.

(May. 1992)

TekTone^® Sound & Signal Mfg., Inc.
277 Industrial Park Road Franklin, NC 28734 USA
Phone: (828) 524-9967 Fax: (828) 524-9968
Sales: (800) 327-8466 Tech Support: (800) 332-6608