[Hallicrafters] Help with SX-99 xfmr replacement

[Phil M.]

Typical color codes for power transformers of this era are green for 6.3 
volt
filament, yellow for 5 volt filament for the rectifier, red for the HV 
secondary
with red/black being the center tap, and finally, black for the primary 
wires.

Good luck with it,
Phil
W5BVB

----- Original Message ----- 
From: "Rbethman" <rbethman at comcast.net>
To: "hallicrafters" <hallicrafters at mailman.qth.net>
Cc: "Rodger" <WQ9E at dtnspeed.net>
Sent: Friday, January 12, 2007 3:19 PM
Subject: Re: [Hallicrafters] Help with SX-99 xfmr replacement


> Roger,
>
> The replacement came directly from a "donor" SX-99.
>
> I see the same color leads in the one I'm trying to get back on the air.
>
> Rodger wrote:
>> Hi Bob,
>>
>> Are the leads you are referring to on the replacement transformer?  It
>> sounds like this is the case and it is not an "exact" replacement for the
>> original-however it may be usable with some changes.
>>
>> Do the black leads have any additional color woven into them?  Using an
>> ohmmeter, see if there is continuity between them or between pairs of 
>> them.
>> Typically, black is used to indicate the primary leads and given your
>> description it sounds like the transformer probably is a dual primary for
>> either 120 or 240 volt service but you will need to ascertain this before
>> using it.
>>
>> The 4 green leads should be two sets of filament windings and given the
>> color coding it is likely that they are both 6.3 volt windings.  The two
>> yellowish/tan leads should be the high voltage secondary but unless there 
>> is
>> a center tap (and it doesn't sound like there is) then you won't be able 
>> to
>> use this transformer with the existing rectifier setup.  Unless there is
>> continuity between the yellowish/tan leads and one of the other leads 
>> then
>> this transformer was designed for use with a solid state bridge 
>> recfifier.
>>
>> If what I have guessed at so far is fairly accurate then you need to 
>> decide
>> whether you want to keep the SX-99 stock or if you are going to try to 
>> make
>> the transformer you have work in it.  You might look at the Hammond
>> transformer line (available from Antique Electronic Supply and others) to
>> see if they have a closer match to the Hallicrafters original.
>>
>> 73, Rodger WQ9E
>>
>>
>>
>>
>
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