Mastr II/ Exec II transmitters can have ~5vdc on mic high, this is
the bias for the amplifier in a normal microphone. If you do not have
a capacitor in series to the computer interface or the computer
interface has a polarized cap that is in the wrong direction, strange
things like this can happen. Verify DC potential on both sides of any
interface components... as capacitors can work backwards for a while
but eventually stop passing when incorrectly polarized...
It is always better to use non polarized capacitors in this audio
path but they do usually cost a little more and sometimes are harder
to acquire...
Doug
KD8B
At 09:37 AM 10/6/2009, you wrote:
The old controller was actually having problems opening up when the radio
went into receive. So it's a bit different. I am trying to get my hands on
another controller to see if that helps. Also may try putting the old
controller back in to see if it starts working any better.
-----Original Message-----
From:
<mailto:Repeater-Builder%40yahoogroups.com>Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Joe
Sent: Tuesday, October 06, 2009 9:20 AM
To:
<mailto:Repeater-Builder%40yahoogroups.com>Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Strange Problem
Are you experiencing the exactly same problem with Echostation as you
had with the old controller? If so, it's probably something wrong in the
MastrII radio. I would troubleshoot this by taking the covers off of
everything so that I can access several points in the transmit audio
chain. I'd take some audio readings with the repeater working correctly,
then wait until the trouble happens and see what changed. At least this
will point you to the area where the trouble is occurring. As I wild
guess, I would suspect a bad capacitor. With MastrII boards being so
easy to get, I would probably just change out the board.
73, Joe, K1ike
Vernon Densler wrote:
>
>
> Here is my setup. I have a MastrII mobile which was converted a long
> time ago. I was having trouble with my controller a while back and
> went with Echostation. As far as I know everything was working fine
> for a while then over the past few weeks I started having this strange
> problem. After being on for about 15 or 20 minutes my audio level on
> the transmit side will drop really low. Most of the time if I unplug
> the cable going from the computer to the transmit side of the radio or
> turn the repeater off then on again it will come back to normal for
> about 20 minutes again.
>
> I tried putting my audio mixer between the computer and the transmit
> on the radio and it didn't fix the problem, however using headphones
> on the mixer I could tell that the audio level from the computer never
> dropped. Which would lead me to believe it's something in the radio.
>
> I also tried disconnecting the ground line from the TX side and that
> didn't help. Going to try both the TX and RX side next so that there
> are no grounds going to the sound card. Besides that is there anything
> else that could be causing this?
>
> Thanks,
>
> Vern
>
> KI4ONW
>
>
>
>
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