PK543 Amplifier Field Test

Many times, in technical support we are asked if there is a way to determine if a product is good without using field connections to check it. Below outlines how to check a PK543 Amplifier in the field for operation:

The tests below are performed with AC power (through transformer) connected to the amplifier. The 16 VAC should be connected to wires C and K.

  • To check the audio functions a pair of 45-ohm speakers can be used with alligator clips (Note: You can use IR104B or IR204B remotes for this test, just use the X and 1 terminals to get direct access to the speaker. Connect one speaker across amplifier wires A and G (entrance panel speaker) and the other speaker connect across 1 and 2. If you speak into the speaker connected to 1 and 2 you should hear audio from the speaker connected to A and G. Next move the connection of the speaker on 1 and 2 to wires 1 and 3. Now speak into the speaker connected to A and G and you should hear audio from the speaker connected to 1 and 3.


  • To check the call tones, connect a 45-ohm speaker across wires 1 and Z or 1 and ZW. A steady tone (for Z) or warble tone (for ZW) should be heard from the speaker.


  • To check the door strike functions, connect a multi-meter set for AC voltage to wires D and K. Short out wires 2 and 3, on the amplifier, and the meter should read approximately 16 VAC. Move the meter probes to L+ and L- and change the meter to read DC voltage. Short out 2 and 3 again and the meter should read approximately 22-24 VDC.


  • Check the input voltage by setting the multi-meter to AC voltage again and place the probes on wires C and K. The meter should read approximately 16 VAC.