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Re: [TenTec] Titan 425 Transformer needed

To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>,<brazos@rochester.rr.com>, <ronc@sonic.net>
Subject: Re: [TenTec] Titan 425 Transformer needed
From: "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 18 Aug 2007 17:44:29 -0500
List-post: <mailto:tentec@contesting.com>
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.

Bob, K4TAX

----- Original Message ----- 
From: "John" <brazos@rochester.rr.com>
To: "Ron Castro" <ronc@sonic.net>; "Discussion of Ten-Tec Equipment" 
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 "_
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
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