[Amps] Ten Tec Titan Troubleshooting Frustration

[Steve, NR4M]

Ken,
I’ve got a homebrew HiPot tester, if you think it could help. 
Steve

Sent from my iPhone

> On Jun 6, 2025, at 4:56 PM, Ken Claerbout <kenk4zw at gmail.com> wrote:
> 
> I've been trying to repair a Ten Tec Titan Model 425 amp and I'm about out
> of ideas.  Here's where I'm at.
> 
> The Soft Start 1.5 amp fuse blows.
> 
> This model power supply has the separate rectifier and filter board,
> mounted on top. The soft-start and bias circuitry are on the lower board.
> With the rectifier/filter board disconnected, the fuse does not blow.  I
> have the gray cable connected between the PS and RF deck but not the HV
> cable.  Anytime I connect the rectifier/filter board the soft start fuse
> blows instantly.  Seems simple enough.  Most likely something on that
> board, bad cap, diode, the usual suspects.  Nope!  Everything checked OK.
> But NR4M had new caps from a project he did so I "borrowed" eight of those
> and replaced the caps.  Still blows.  Replaced diodes and resistors.  Same
> thing, fuse blows.  Everything on the board has been replaced at
> this point.  I don't see any burned traces on the board, like what happens
> sometimes.
> 
> I pulled the lower board and looked it over.  I don't see anything wrong
> with it either.  I don't see any DC shorts on the transformer.  I've had a
> few of those go bad in the past.  They take out the 20 amp line fueses and
> I can measure the short.   So to recap
> 1.  The soft start fuse is blowing
> 2.  It doesn't blow with the rectifier/filter board disconnected
> 3.  All components have been replaced on the rectifier/filter board.
> 
> What am I missing??
> 
> 73
> Ken K4ZW
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