[TenTec] Model 260 PSU problem

[Steve Hunt]

Jerry,

Just to report that the PSU is now repaired and working well. I'll keep an eye on the Diode Bridge case temperature for a few days to check the heat-sinking is OK.

Yes, I drilled a new hole midway between the TO-3 mounting holes, and a corresponding one in the bottom of the case. I could have used one of the existing TO-3 holes, but I felt it was better to have the new bridge sitting centrally in the heat sink. I was careful to "deburr" the new holes so that bridge "sat" flush on the sink, and the sink sat flush against the case.

The PSU is now very much quieter. Hardly surprising when you think that the transformer was supplying nothing on one half-cycle, and lots of current on the other half-cycle!!

73,
Steve G3TXQ
  ----- Original Message ----- 
  From: Dr. Gerald N. Johnson 
  To: tentec at contesting.com 
  Sent: Friday, December 01, 2006 11:01 PM
  Subject: Re: [TenTec] Model 260 PSU problem


  On Fri, 2006-12-01 at 22:41 +0000, Steve Hunt wrote:
  > Jerry,
  > 
  > Thanks for your advice.
  > 
  > I have catalogues for all the main UK component distributors, but none stock a diode bridge in the same package as the one in the Model 260. It's a package I've never seen before. Take a look at:
  > 
  > http://hoffind.com/ipw-web/productpage/images/VT400T.JPG
  > 
  > So I guess I'll just have to adapt the more usual 1" square packaged part.
  > 
  > 73,
  > Steve G3TXQ

  I've seen that package in catalogs. Never in the solid though. Likely
  the flange matches a TO-3 case. So I guess you need a new hole in the
  heat sink right in the middle.
  -- 
  73, Jerry, K0CQ,
  All content copyright Dr. Gerald N. Johnson, electrical engineer

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