[Hammarlund] Comet Pro Trasformer Went South

[Robert Sauvan]

I just received a new transformer custom wound for my Hallicrafters 
HT-30 transmitter and it was half the price of a rewind. I only paid 
$125.00 for this new transformer from Heyboer Transformer out of 
Michigan. I would suggest checking them out before you rewind the existing.

Bob-W0YBS




On 7/14/2013 8:47 PM, Kenneth G. Gordon wrote:
> Transformer is internally shorted. Get it rewound.
>
> Ken W7EKB
>
> On 14 Jul 2013 at 18:06, Joe Connor wrote:
>
>>
>> I picked up a Hammarlund Comet Pro at a hamfest today. I changed the
>> filter caps, ran it on a variac at about 105V and got it playing. Then
>> the power transformer went. I want to go through my diagnosis just to
>> make sure I've eliminated any possibilities other than the power
>> transformer. I also want to get any ideas anyone may have on a
>> replacement.
>>
>> Diagnosis: The xformer started smoking with the unmistakable bad odor.
>> B+ dropped badly and the receiver stopped playing. I pulled the
>> rectifier tube and the xformer still overheated. I replaced the
>> rectifier and disconnected the lead from the rectifier to the first
>> filter cap/filter choke and it still overheated. Resistance between
>> the filaments on the rectifier socket (with the rectifier removed)
>> measured 0.1 ohms. The plates on the rectifier socket measure 194
>> ohms. Plate to ground measures 112 ohms and 82 ohms. I just want to
>> make sure it's the power xformer. I have restored close to 100
>> boatanchors and this is the first power xformer I've had go south. I
>> guess I was living on borrowed time (or else replacement of filter
>> caps before the initial fire-up really does avert a lot of
>> disasters).
>>
>> Replacement: Any ideas on replacement?  This set uses tubes with 2.5V
>> filaments so I'm sure my options will be limited. This set is pretty
>> beat up so I'm not sure how much I want to spend. On the other hand,
>> without a new xformer, this set is just a big doorstop. There is space
>> on the top of the chassis for a separate plate transformer, if
>> something like that is possible.  Of course, if anyone has a junker
>> laying around with a good xformer, I would be interested in buying it
>> (along with a few other non-essential parts that are missing from
>> mine)
>>
>> As always, thanks for your help and guidance.
>>
>>
>> Joe Connor
>> ______________________________________________________________
>> Hammarlund mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Hammarlund at mailman.qth.net
>>
>> List Administrator: Duane Fischer, W8DBF
>> ** For Assistance: dfischer at usol.com **
>>
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
>
> Kenneth G. Gordon W7EKB
>
> "Courage is being scared to death but saddling up anyway."--- John   Wayne
>
> ______________________________________________________________
> Hammarlund mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hammarlund at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>