The Radio Information Board

My Ext Speaker will not work most of the time. Sometimes when high modulation signals are received like page tones, or load operators the speaker play sound. But most of the time it is silent. One unit was taken into the radio shop when the outside speaker was not working. (going through siren box). The shop placed a device (transformer) now the outside speaker pops and squeals all the time.

Found it to be a issue with the siren amp. Unplugged it and Secondary speaker now works. But unable to play it out side. The radio shop placed a transformer inline work but outside speaker pops and squeals all the time. Any ideas would be helpful.

How many speakers do you have on the radio, and how are they connected?

I'm not familiar with "how the siren box works"...however, you could try connecting the external speaker directly to pins 1 & 2 of the radio accessory connector (that's the black one) as an experiment to see what works. If you have an internal speaker in the radio control head, pin 1 also has to stay connected to pin 3 for that to work. Also, the speaker should not be grounded (maybe that's why the transformer was used?)

See this thread for more info: viewtopic.php?f=16&t=4478
PM me if you need accessory connectors and pins.

--Don

We had the same problem installing an ES in an armored vehicle. Turns out, some siren units have a low input impedance that causes the EFJ's audio PA to shut down. I inserted a 1500ohm resistor in each lead going to the siren unit, and that fixed the problem.