Re: Blew up QCX with GPS - repair advice?


Alan de G1FXB
 

Another possible if heat-sinking hasn't / doesn't save it,
is to perhaps lessen the dissipation of the PA*.

The easiest being reducing the input voltage while using high duty cycle modes
 such a WSPR ??

* Class E output stages by their nature can be subseptable to component failure through excessive Vs caused by many external factors.
Inc antenna mismatch etc.


Alan

On 08/08/2018 23:36, Alan de G1FXB via Groups.Io wrote:

Is the warning contained in section 4.24 Beacon menu in the assembly manual relevant?


Alan


On 08/08/2018 23:24, BobVA wrote:
On Tue, Aug 7, 2018 at 06:04 PM, Kent Vanderploeg wrote:
Just following up on my progress and to see if Bob has had any luck getting his going again.
  I'm afraid I'll not be much help.  Replacing Q1-Q6  got me back to about 3.5w into a dummy load on 20m at 14v (not a great wattmeter, so take that with a grain of salt).
    I then reconnected all the WSPR bits but unfortunately forgot to peak my small loop on the WSPR frequency before transmitting (it was close, but...), so that took out the finals yet again (shorted this time).
     I replaced just Q1-3 and Q6 again which got the RF back, and then *carefully* set it and the antenna up for WSPR.  It transmitted happily for a couple of hours, putting out about three watts. 
   Then some other failure ensued that resulted in a blank display.  After a cycling power I had no RF again, so I'm beginning to suspect I've either got another fault in the radio that is causing the finals to fail, or it *really* doesn't like something about my antenna setup. 

  73,
   Bob


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