[arm-allstar] CM108 sound fob mike input low level

Doug Crompton wa3dsp at gmail.com
Thu Aug 3 12:59:48 EST 2017


Alan,

 I am still not clear on what you have there? Did you say you have one of
the open boards? Did you modify it? If so what resistors did you use on the
if any on the RX and TX audio lines? You talk about Startech and I am not
sure what that has to do with the new non-case open board? The audio in and
out of the open board seems to work best with series 5-10K resistors. If
you need additional gain they can be removed. Photos are on the the USB FOB
mod howto on the hamvoip.org web page.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*




On Thu, Aug 3, 2017 at 1:38 PM, "Alan Matthews via arm-allstar" <
arm-allstar at hamvoip.org> wrote:

> Hi guys
>
> it looks as if the cm108 chips I have are CM108B. Doug mentioned removing
> a resister in the fob, I have not removed any components from mine.
>
> could someone give me a heads up on what mods are required please,
> photographs would be useful. i am using the circuit design that used the
> original startech fobs, these work great but have become extremely
> expensive.
>
> Any help advise as to what needs doing to these fobs would be great, I
> don't want to go down the road of installing a pre amp.
>
> thanks in advance.
>
> Alan
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