[1000mp] More info on MkV blown front end.

Tue, 2 Sep 2003 04:12:40 +0100

something similar happened to me.  Unfortunately I was transmitting at the
time and the rf went into the RX unit. Kablooey.

----- Original Message ----- 
From: "Watt Gee" <[email protected]>
To: <[email protected]>
Sent: Tuesday, September 02, 2003 4:15 AM
Subject: Re: [1000mp] More info on MkV blown front end.

> Hi Guys. I have a mark V about 8 months old.  Has this happened to many
other people?
> Also is there anything else that I should watch out for?  Running scared.
Watt n5nf
>
> "George, W5YR" <[email protected]> wrote:
> Sound like the transistor is just a simple switch for the relay. When the
> relay should be on, the base should be at an appropriate voltage for the
> circuit in order to turn the transistor on. If the base is being switched
by
> the T/R logic and the relay doesn't come on, that pretty well points to
the
> transistor as being defective - replace it. If no base voltage change is
> observed, then start working backwards through the T/R logic from there.
>
> I wouldn't want to argue about it, but a curve tracer to evaluate the
> transistor is a little overkill. It either switches or it doesn't.
>
> 73/72, George
> Amateur Radio W5YR - the Yellow Rose of Texas
> Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
> "Starting the 58th year and it just keeps getting better!"
> [email protected]
>
>
>
>
>
> ----- Original Message -----
> From: "Darrel Nichols"
> To: <[email protected]>
> Sent: Monday, September 01, 2003 9:32 AM
> Subject: RE: [1000mp] More info on MkV blown front end.
>
>
> >
> >
> >
> > > [Original Message]
> > > From: lhlousek
> > > To: 1000mp list <[email protected]>
> > > Date: 8/31/2003 11:10:10 PM
> > > Subject: [1000mp] More info on MkV blown front end.
> > >
> > > I did some troubleshooting. There is a T/R circuit at the antenna
input
> > to the rig that employs three transistors, a pin diode switch, and a
> > relay. The relay isn't being activated. I can make the relay work by
> > supplying 12V to it and the rigs receives fine. The PNP transistor that
> > operates the relay is either blown or isn't getting the correct input to
> > switch the relay. I need to do some more signal tracing to see if I can
> > figure out what's going on.
> > >
> > > Lou W7HV
> > >
> >
> >
> > Sounds like a job for a Curve Tracer. Found a page:
> >
> > http://www.old555.com/LPE/unit/5B680B4E0BE5E522.shtml
> >
> > Been using these for over 30 years and still am surprised to learn
> > some don't know about it. You do need a simple scope though.
> >
> > N0DBX
> >
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