Bogen PI35A Intercom System User Manual


 
Troubleshooting Guide
MCP35A Troubleshooting Procedure
If a problem exists on the MCP35A, certain steps should be taken to find the problem. This test relates to the
Program Amplifier (All-Call or Emergency). The first indication of a problem will appear on the three level indi-
cators at the front of the unit. They are green, yellow, and red.
If there is no problem, the green, yellow and/or the red LED should flicker whenever audio is present, depending
on the signal strength. A problem is indicated when the red LED does not flicker no matter what level the pro-
gram control is set to.
To find the problem, follow this simple procedure:
1. Disconnect the switchbank(s), SBA225, from the MCP35A and depress the emergency button. While speak-
ing into the built-in microphone, adjust the Program Level Control and check the level indicators as described
above. If all three indicators can be made to light depending on the output level control setting, then the
MCP35A is okay.
2. Connect only the first switchbank (if more than one is being used). With the speaker load still connected,
check the level indicators again.
3. If the MCP35A LED’s still indicate a problem when connected to the switchbank, each speaker location on
that switchbank being tested should be removed one at a time, until the level indicators show a normal out-
put. The speaker and cable associated with that location should then be checked.
4. Follow the same procedure, connecting each successive switchbank until the troublesome SBA225 panel or
speaker load is found.
5. If the MCP35A is tested without the switchbank, and the three LED’s do not ‘light’ indicating full output, then
the 35-watt program amplifier of the MCP35A may be defective. Contact the Bogen Applications Engineering
Department for assistance.
If it appears that there is no intercom communication between the unit and a speaker station, the 20-watt
intercom amplifier inside the MCP35A may be defective. Contact the Bogen Applications Engineering
Department for assistance.
Caution
Do not attempt to connect a 25V speaker directly to the MCP35A using GND as one of the connecting
points. This could seriously damage the MCP35A because the unit uses a balanced output when con-
nected to the speaker lines.
21