[Premium-Rx] Watkins Johnson 8615D receivers

[JJ]

Al least two of my many WJ receivers had shorted tantalum bypass cpacitors so this seems to be a root cause of many power supply supply issues - when high current draw is measured look at these caps.  SDU shieded DC-DC converters were opened-up by yours truely and shorted tantalum bypass caps were identified and replaced.  

I suspect a bad batch as my repairs have lasted over 9 years..

 Joe Jesson

  ----- Original Message ----- 
  From: Geoff Greer 
  To: Royce, Alan (ST) ; Jim Garland ; spencer bahner ; premium-rx at mailman.qth.net 
  Sent: Monday, January 19, 2009 11:47 AM
  Subject: Re: [Premium-Rx] Watkins Johnson 8615D receivers


  Hi Group,

    The power supplies were a purchased item.  You will have to contact the power supply vendor for any info.  BTW, the 9040 series power supplies were also a purchased item.  I have seen several different vendors for those.

  Regards,
  Geoff 
    ----- Original Message ----- 
    From: Royce, Alan (ST) 
    To: Jim Garland ; spencer bahner ; premium-rx at mailman.qth.net 
    Sent: Monday, January 19, 2009 9:45 AM
    Subject: Re: [Premium-Rx] Watkins Johnson 8615D receivers


    Does any one know where the power supply FET's, SCR, and the glass diodes can be purchased?
    May be some one knows the replacement part numbers?
    Thanks
    Al



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    From: premium-rx-bounces at mailman.qth.net [mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of Jim Garland
    Sent: Monday, January 19, 2009 5:32 AM
    To: 'spencer bahner'; premium-rx at mailman.qth.net
    Subject: Re: [Premium-Rx] Watkins Johnson 8615D receivers


    I don't know the exact part used in your WJ receiver, but in receivers I always use NTC Inrush Current Limiters, part no. CL-140, available at www.mouser.com .  These are rated at 50 ohms cold, with a maximum stead state current of 1.1A. They cost about a dollar.

     

    73,

     

    Jim Garland W8ZR

     


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    From: premium-rx-bounces at mailman.qth.net [mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of spencer bahner
    Sent: Sunday, January 18, 2009 10:28 PM
    To: premium-rx at mailman.qth.net
    Subject: [Premium-Rx] Watkins Johnson 8615D receivers

     

    All-
     
    If any of you have worked on any Watkins Johnson WJ8615D receivers that have had the small inrush current limiters on the AC input to the switching supply fail (killing AC power to the power supply), and you have ANY idea as to the proper replacement part, please send me an email or post for the group. This seems to be a common failure item when the receiver is completely dead. Working units often have these showing dark discoloration due to high heat disipation as they limit initial series current upon receiver power-up.
     
    Thanks all!
     
    Spencer Bahner N7UMO



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