SYSTEMS SABER Tinny Transmit Audio

[RFI-EMI-GUY]

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

[DJP126]

Try swapping out the VCO or power amp modules.