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Smoke with first transmit of 6700, DIPS, 2MLDPA, and L432 Transverter

I had a bad electrical burning smell when I tried transmitting on the 2MLDPA for the first time with my 6700, DIPS, 2MLDPA, and a L432 transverter.  I connected all parts per the Q5 Signal/DEMI block diagram.  The 6700 was set to transmit at about 10W out of the 2MLDPA.  Best I can tell, I did not burn anything out, but I am still checking.  After the test, the DIPS felt very warm.  The 2MLDPA was purchased with the remote option and control cable.  When I did this test, the L432 transverter was not powered.  In the past, I successfully transmitted on the 2MLDPA when it was connected directly to the 6700 with no DIPS or L432 connected. I have gone back and checked VSWRs of the transverter port of the DIPS when all boxes were connected per the block diagram, except for the cable to 6700 transverter port.  When in receive mode, the VSWR of the DIPS transverter port was 10, but then dropped under 2 across the 2m band when switched to transmit. I have also checked the VSWR of the L432 28MHz port when it is not powered and that is under 2.

Does anyone know what I may have done wrong or can you suggest other tests to perform to get to the bottom of this?  I am a little skittish to try transmitting on the 2MLDPA again with the DIPS and L432 connected until I get to the bottom of this.

I appreciate any advice you may have! 
Jeremy
W2JG

Answers

  • SteveM
    SteveM Member
    edited January 2020

    Well, according to your description of the smell, you ought to be able to sniff-out which component lost some of its smoke. There should be some smelly residue left somewhere.

    It puzzles me why the DIPS should have felt "very warm". There shouldn't be enough power transferred through it to cause it to heat up. It seems to me the only possible thing that could have gotten hot is the amp or, unlikely, the feed from the amp.

    You told us everything was properly connected and SWRs are good. There is not much any of us can say except, maybe, "a picture is worth a thousand words".


    Good luck!
  • Jeremy - W2JG
    Jeremy - W2JG Member
    edited January 2020
    Well it looks like my 2MLDPA may have been on its way out.  Today I connected it to a dummy load and loaded the L432 side of the DIPs and went to full power.  After about 10 seconds, the RF indicator bar on the 2MLDPA went dark.  I have already contacted Q5 Signal and they are very cooperative and offering to look at and probably repair the unit free of charge, assuming I did nothing wrong.  I will run a few more tests before sending the unit back.

    My guess is that this occurrence and the one that I originally posted about are related.  I will keep this thread alive until I get the status back from Q5 signal in case anyone following this is interested.

    Thank you everyone for reading this and for SteveM's reply, I greatly appreciate it!  This thread likely has nothing to do with the Flexradio 6700, but it does utilize equipment that is required to make use of the 6700's 2m capability.
    I will keep you posted...

    Jeremy
    W2JG
  • Jeremy - W2JG
    Jeremy - W2JG Member
    edited February 2020
    I heard back from Q5 Signal today.  A part in the DC power circuit blew out.  Corey, the head of the company, said there was nothing I did that would have caused the problem.

    This closes this thread.

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