[DEMI] DEM 144-28

George Fremin III - K5TR geoiii@kkn.net
Sun, 2 Jun 2002 06:45:33 -0700


Some of you maybe recall this message I sent last year.


> Date: Thu, 21 Jun 2001 07:11:51 -0700
> From: George Fremin III - K5TR <geoiii@loja.kkn.net>
> To: demi@kkn.net
> Subject: DEM 144-28
> User-Agent: Mutt/1.2.5i
> 
> 
> Hi,
> 
> 
> I have a DEM 2m transverter that has been working very well.
> This morning I was using it and I lost output.
> 
> It also seemed like I lost some RX gain but maybe some 
> noise just went away because I seem to hear as well 
> on it as I do on my Kenwood TR-751a.  I can hear a beacon
> that is 200 miles awy etc.
> 
> All the voltages on TX and RX look normal per the manual.
> 
> If I key it on CW I get about 500mw or so output.
> The output IC does not get warm.
> 
> So I am thinking the output IC might have died.
> 
> I had been transmitting quite a bit before I lost output.
> 
> Comments?  Thoughts?
> 
> Thanks
> 
> -- 
> 
> George Fremin III                 
> Johnson City, Texas             "Experiment trumps theory." 
> K5TR (ex.WB5VZL)                            -- Dave Leeson W6NL
> geoiii@kkn.net                             
> 830-868-2510                      
> http://www.kkn.net/~k5tr                   
> 

Well - I now I the same symptoms again.

Low TX power - about 1 watt or less.
Low RX sensitivity - sounds like a bit more than 20db.

The LO is right on frequency.

Last time I ended up sending it to DEM and they fixed it 
and I think I paid like $25 - as I recall there was no 
notation as to what was fixed. 

On other data point - it failed two other times before dying totally.

It seems that after some extened periods on the air I got 
the entire transverter quite warm and these same symptoms 
occured but after it cooled off it all worked again.

I have sort of checked the T/R relay and it
does not seem to be the problem.

ie. I have routed around it. 
The IF paths seems to be fine to and from the IF radio - the 222 and 432
transverters are acting ok.

I am bummed.

-- 
George Fremin III - K5TR
geoiii@kkn.net
http://www.kkn.net/~k5tr