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How To Fix A Stuck Touch Plate Low Voltage Switch

Stuck Switches in Touch Plate Low Voltage Systems

You might have a stuck switch in your Touchplate low voltage system if something that is ON stays ON indefinitely, or if something that is OFF permanently stays OFF. To learn how to fix a stuck momentary switch, first troubleshoot your wiring system by checking the transverter to ensure the appropriate voltage is being output from your low volt system.

How to Fix A Stuck Low Voltage Switch in Touch-Plate Systems

If you suspect that one of your Touch-Plate low voltage switches is defective, first test your transverter power supply to see if the appropriate voltage is being output. 

tip.jpgCheck your transverter by going to the relay panel where the transverter in your system is housed. When operating normally, the system should be outputting 28 to 31 VDC with nothing connected. If the voltage output is 2 to 4 VDC (or even 0 VDC) with the wires connected, a stuck switch is holding the circuit closed and the transverter has lowered its voltage output as a protective measure against burning the relay coil. With this, the defective (stuck) switch will have to be replaced or fixed. 

info-voltage.jpgIf your transverter has a normal output of 28 to 31 VDC and your system is still not functioning properly, you could have an internal wiring problem. Something could be disconnected (loose wires) or a wire may have been improperly reconnected after changing a component. Please refer to a licensed electrician for further assistance with these issues involving your inside wiring. 


You should consider replacing your transverter if the voltage output is between 4 VDC and 28 VDC. Touch-Plate's latest 120V transformer model, TPS-0120, directly replaces the discontinued Touch-Plate TVR-1 transverter as well as the older 17C converter and 78K1 transformer combination power supplies. 


We highly recommend consulting a licensed electrician for help if you have any reservations about performing the troubleshooting steps above, or if you are concerned about the presence of dangerous voltages. This troubleshooting advice is limited to Class 2 low voltage wires only; for your safety, please DO NOT attempt to troubleshoot any high voltage wiring.


How to Find Which Switch Is Stuck in a Touch Plate Low Voltage System

If you are suddenly unable to turn on or off any of your lights in your Touch Plate system, a stuck switch may be the cause.

Switches can get stuck in a couple of ways. One, the switch physically is jammed or two, the contacts have fused together. When this happens, the transverter is continually putting current through the last relay that was switched on or off thereby preventing it from switching any relays.

The transverter (TPS-0120 or TVR-1) and the relay that has the stuck switch will most likely feel warm to the touch.

info-caution.jpgPlease Note: Perform the following at your own risk. Although shock is not likely because the low voltage side of the transverter (the side with the two thinner wires) is only about 30 volts DC, nevertheless it is not impossible. If you are unsure whether dangerous high voltages are present, then contact an electrician to perform these tests for you. You should be able to use a simple voltmeter or multimeter to test for the presence of high voltages. Be sure to check for high voltages using both AC and DC modes.


Now to help you find that stuck switch:

To find the relay with the stuck switch, locate the transverter's two SMALL THIN wires which are connected to the relays and switches. Disconnect ONE of the SMALL wires from its connection. You now have 2 bare wired ends. One is going to the transverter, the other is going to the rest of the system. When you touch these two bare wires ends momentarily, a relay should click over. Do this several times in succession to locate the sound of the relay. You should also see one of your lights turning on and off. When you find the relay, it should be warm or hot if it has not been too long since the connection at the transverter was broken. If you disconnect this relay on its low voltage side (either of the two low voltage wires), your system should be freed up, allowing you to control the rest of your lights. If you still cannot, check the voltage at the transverter (low voltage side). If it is about 30V DC, then it probably needs to be replaced. If it is about 3V DC, then you probably have another stuck switch, or you have disconnected the wrong relay and you should repeat the above procedure.

Theory of Operation: The transverter is at rest most of the time. Its "at rest" voltage is about 28-30 volts DC. When a button is held down, the relay switches, and the transverter's voltage drops to about 3 volts DC until the button is released. This can be simulated with a working system: just hold down one button, then, about a second later, with the button still held down, try pressing another button. It shouldn't work until the first button is released. The troubleshooting procedure above works because the two bare wire ends become the "switch", since the stuck switch is not just a constant electrical path.

In brief, the testing procedure is as follows:
1. Disconnect one of the low voltage wires at the transverter.
2. Momentarily touch the resultant two bare wire ends together.
3. Follow the clicking sound, and disconnect one low voltage wire on the relay that is clicking
4. If the lights work now, find and replace the stuck switch.
5. If the lights still do not switch: check the voltage across the low voltage side of the transverter. If it is about 30VDC, you probably need to replace the transverter.
6. If the voltage is about 3VDC, you probably still have a stuck switch that is connected to a relay other than the one that has been disconnected.

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