[TenTec] Model 260 PSU problem

[Steve Hunt]

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
  ----- Original Message ----- 
  From: Dr. Gerald N. Johnson 
  To: tentec at contesting.com 
  Sent: Friday, December 01, 2006 7:46 PM
  Subject: Re: [TenTec] Model 260 PSU problem


  On Fri, 2006-12-01 at 19:23 +0000, Steve Hunt wrote:> Folks,> > It's turning into "one of those weeks"!> > I couldn't understand why my new Omni VI was "unhappy" at full power when fed from my Model 260 PSU, but was fine on the Hercules II supply. I just had a look with the 'scope at the 13.8v line from the PSU. At anything approaching full load there was several volts of ripple.> > A bit more fault finding and it turns out the main diode bridge is open circuit on one side; the clue was that I was seeing 50Hz ripple, not the 100Hz you would expect from a full wave bridge circuit.> > The faulty part is a "Varo R207T". TenTec would probably carry a spare, but it seems a bit unnecessary to ship from the US if I can find a suitable alternative here in the UK. But I can't find any reference to the R207T through Google and so don't know what the spec is.> > My local electronics store has a KBPC3504 rated at 400V PIV, 35A Ifavg, and 400A surge current costing just £1.60. It's the wrong case style but it would be no problem to fit it on the same heat sink.> > Any views from listers whether this would be a suitable replacement?> > 73,> Steve G3TXQ> 
  I'd think that for £2.60 at one of the good UK radio parts places youshould find one with the same package too. 35 amps and 100 volts isprobably good enough, 400 volts won't hurt. Which ever it will need theheat sink and keep the white stuff as thin as possible and the rectifierwill run cooler.-- 73, Jerry, K0CQ,All content copyright Dr. Gerald N. Johnson, electrical engineer
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