Batboard

OK; I am working on my "fleet" and I have this one UHF SYSTEMS SABER III that is exhibiting tinny transmit audio. At first I was testing in secure mode (DES) and thought it was the NTN5835A DES-XL module that I am running with the XL disabled, but then I compared in analog FM mode and sure enough of the three radios, another model III and a model I, this one is tinny and weak. So I checked the mic gain, it was +3 dB like the others. I pumped it to +6 dB and although louder still tinny. So I then swapped the speaker and mike assembly from a donor radio, Same old same old.

Any thoughts where this might be going? It is an intrinsically safe housing, I am not sure if those had a membrane of any sort, but I would think audio would be muffled not tinny. I guess I could swap housings, but if it is some weird programming issue...

Also some of the newer radios (1995 vintage) have a foam/metallic pad behind the front cover. Does anyone know when they started installing those and what it is supposed to fix?

Thanks

Try swapping out the VCO or power amp modules.