Re: [TenTec] Titan 425 Transformer needed

["Bob McGraw - K4TAX" <RMcGraw@Blomand.net>]

According to the Peter Dahl website, 
http://www.pwdahl.com/dahlcatalog/hamtrans011404.html#T, they have two 
transformers.  $350 each for the Titan.  One has a higher secondary HV 
winding than the other.  They are 1270 VAC @ 1 amp CCS and 1800 VAC @ 1.2 
amps CCS.  Both weigh 46 lbs. and the same price.
For the Centurion, $325 and the Dahl website lists the HV secondary as 2225 
VAC @ 0.5 amps CCS.  Now, that raises a serious issue.  The Centurion uses a 
voltage doubler in the HV circuit.  That configuration with the above 
transformer would be very unsatisfactory as a direct replacement as the 
rating of the filter caps and the tubes would be greatly exceeded. 
Otherwise, voltage twice what it should be and current about 1/2 of what it 
should be.  If the transformer data is correct then the rectifier circuit 
should be changed to a FW bridge.
I'd get clarification from Peter Dahl as to the exact specs for these 
transformers before I put one in my amp.
73
Bob, K4TAX


----- Original Message ----- 
From: "John" <brazos@rochester.rr.com>
To: "Ron Castro" <ronc@sonic.net>; "Discussion of Ten-Tec Equipment" 
<tentec@contesting.com>
Sent: Saturday, August 18, 2007 5:00 PM
Subject: Re: [TenTec] Titan 425 Transformer needed


> How much would a Peter Dahl Transformer be for the 425 or centurion ? 
> John
> kb2huk
> ----- Original Message ----- 
> From: "Ron Castro" <ronc@sonic.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Saturday, August 18, 2007 3:03 PM
> Subject: Re: [TenTec] Titan 425 Transformer needed
>
>
> > The primary to secondary short is a known problem with the 425's, and 
> > mine
> > went back to the factory some years ago for a replacement which is still
> > running fine today.
> >
> > You can't go wrong with a Peter Dahl transformer as a replacement, but I
> > would suggest calling them on the phone.  Here is a link to an article
> > about
> > beefing up the venerable 425 which is good for future reference even if
> > you
> > keep the finals and the plate voltage the same.  The author used a
> > specially
> > built Peter Dahl transformer for the project which turns the 425 into 3.5
> > kW
> > ground pounder!
> >
> > http://www.hamradiomarket.com/articles/Titan%20P%20Hybrid.htm
> >
> >         Ron N6IE
> >      www.N6IE.com
> >
> >
> > ----- Original Message ----- 
> > From: "Carlin Royal" <n5oe@nctwb.net>
> > To: <tentec@contesting.com>
> > Sent: Saturday, August 18, 2007 11:49 AM
> > Subject: [TenTec] Titan 425 Transformer needed
> >
> >
> > > Sorry for the long delay on the re-post. After replacing/upgrading the
> > > rectifier board, installing new filter capacitors the initial problem is
> > > still there. I carried the amp to a local repair shop and it has been
> > > determined for sure the secondary leads have shorted with the primary in
> > > the transformer. SOOOO I am in need of a new transformer for the Titan
> > > 425 at this time. Since I have already come this far money wise and time
> > > wise, I think it would be best to get a "really good" transformer this
> > > time. I have emailed Peter Dahl with no response, are they still doing
> > > this sort of thing for amateur use?
> > >
> > > _"I have a Ten Tec Titan 425 that I have only had myself for about 6
> > > months now.
> > > The amp when I received it had 1 bad HV capacitor in the power supply.
> > > Due
> > > to
> > > lack of funds at the time I replaced the one known bad capacitor. A few
> > > months
> > > later I was operating the amplifier during a cw pileup for about 30
> > > minutes, I
> > > set everything on standby and went to lunch. When I returned to the 
> > > shack
> > > I
> > > find the amp had blown one of the 20amp fuses in the supply.
> > > After checking in the PS, I found that R1 the 10ohm 25watt wire wound
> > > resistor
> > > on the rectifier board had went open. I replaced the blown resistor and
> > > powered
> > > the amp back up, this time again blowing a 20ampfuse and the same
> > > resistor. Ten
> > > Tec advised to replace the original rectifer board with a new one, 
> > > (82112
> > > rev E
> > > I beleive) since they thought some diodes were probably leaking and was
> > > the
> > > cause of all my troubles. Now after replacing the old rectifier board
> > > with
> > > the
> > > new one from Ten TEc, I power the amp on and it blows another 20amp fuse
> > > but
> > > did not appear to fry the resistor this time. Here is the main question
> > > to
> > > the
> > > list; Could I have another bad capacitor that is failing under high
> > > voltage
> > > since they do not read any shorts on the VOM when individually beng
> > > tested. I
> > > have on order 8 new 400uf 450v caps from Newark Electronics and will be
> > > replacing them this week, but I am looking for more input as to the
> > > trouble. It
> > > just seems odd to me that when sitting idle for just 3
> > > 0 minutes the thing went south and now I have had all this trouble.
> > > Hopefully
> > > I am on the right track and it will be one of the caps in the PS, but
> > > would be
> > > interested to hear any other areas that I might could check within 
> > > reason
> > > here
> > > on the very limited bench. Thanks for any advise/comments.
> > > 73 "_
> > >
> > >
> > >
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