TCS Keep-Alive® (KA) devices are used to supply power to decoders during times of power interruption due to dirty track or problematic track work.

Newly-redesigned and coming in at half the size of a KA4, the KA2 will power HO or N scale locomotives with approximately one-third of the capacitance of KA3/KA4 devices (depending on the locomotive and motor).

This Keep-Alive® includes a 2-Pin Quick Connector Harness for plugging into decoders with a compatible socket. , such as the T4.

• Dimensions: 0.35" x 0.35" x 0.61" or 8.9mm x 8.9mm x 15.5mm
• Scale: HO Scale / N Scale
• Input Rating: 12 to 16V

Additional information from TCS:

Keep Alive® Decoder Compatibility With TCS Decoders
TCS Keep Alive® (KA) devices are designed to operate with all TCS (or any other Keep Alive® ready) decoders. Decoders with a corresponding socket can be used with the KA2-P. This will be detailed in the decoder literature if the decoder has the socket.
!!!WARNING!!! Decoders with a “-KAC” suffix have a non-polarized 2-Pin Connector for attaching the KA(x)-C. The KA2-P is NOT compatible with this style of plug-in Keep Alive® interface.

Keep Alive® Decoder Compatibility With Non-TCS Decoders
If you would like to attach a Keep Alive® unit to a non-TCS decoder, you need to connect the wires across the output of the bridge rectifier on the decoder. You will need to consult your decoder manufacturer for a schematic or wiring diagram.