Sunday, December 1, 2019

Potential Astron power supply failure solved!


One of my blog readers informed me regarding the Astron linear power supply that the outer case on the pass transistors at the rear of the supply are live with about 24 volts.  These pass transistors are isolated from the case and the heat sink so the potential is there to inadvertently via a PL259 connector, USB cable or any other conducting item at the rear of your setup to short the pass transistor and destroy them.  This morning I once again was searching the internet to see if anyone had devised a solution for this very issue. I came across a web page . This individual has the RS-35A power supply and came up with a great solution using a 3D printer. Now I am not at all up on the whole 3D printer thing but click on the link  above (web page) and have a look at the pictures they posted. The covers look great and are very professional looking. It would look to me the plans are available to those who have access to a 3D printer to produce the guards them self.  I would really like a set of these for my RS-25 but just short on the 3D printer part of things.
To my fellow bloggers have a look at the above link and do post any 3D printer info you may have as well.

As a side note below are some links to great information regarding Astron power supplies.

http://www.wb1gof.org/files/AstronPDF.pdf

http://www.repeater-builder.com/astron/pdf/astron-troubleshooting.pdf

http://www.repeater-builder.com/astron/astron-repair/astron-repair.html

https://www.ecse.rpi.edu/courses/CStudio/ham_radio_docs/astron-repair-index.htm

4 comments:

  1. I think it is the same for all Astron power supplies I guess. Good solution to guard them. I have another solution...the pass transistors are now at the bottom. And I don't have the supply at my desktop but beneath it....on wheels. See this picture: https://3.bp.blogspot.com/-6Jqu7E9bxUo/UipF7C7CS2I/AAAAAAAAGKc/EXAgnKQeVYY/s1600/Voeding.jpg 73, Bas

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    1. Good evening Bas and as always very nice to hear from you, that is a very nice idea and very portable for a heavy supply. The idea of wheeling it around is very nice.
      73 and have a good week Bas......oh and while on FT8 I have contacted a few hams from the Netherlands, and I am waiting to contact you and Paul.
      Mike
      VE9KK

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  2. I believe the pass transistors are TO3 case (or similiar). Case covers are available
    Quick look:
    https://www.digikey.ca/product-detail/en/keystone-electronics/4632/36-4632-ND/316222
    Enjoy reading your blog and blogs you follow - 73, VE3BJY

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    1. Good evening and thanks for taking the time to read and leave a comment, I looked at the digi key link (digi key is a great place by the way) but I was wondering if by covering the pass transistors with a plastic cover would reduce the transistor's ability to dissipate heat? I am not sure but was just wondering
      Have a great week
      73,
      Mike
      VE9KK

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