[Heathkit] DX-40 Pwr Xfmr

[Garey Barrell]

Bill -

Sorry to hear that....

Just as an aside, if you have a Simpson 260, (or another analog meter with a Polarity switch 
effective on the Ohms range,) you can test for shorted turns.

Set the meter to read the resistance of any winding on the transformer at around 2/3 of full scale.  
Then switch the Polarity switch.  If there are NO shorted turns, the meter needle will give a sharp 
kick before settling back to the correct reading.  If the transformer DOES have a shorted turn, 
there will be only a very small kick, if any,  when polarity is switched.

This is one of those subjective tests that is a lot easier to interpret once you have seen the 
results a couple of times.   You have a good test specimen!

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>


Bill Stewart wrote:
> The verdict is in...its shorted. I took it out and put 60vac on it and its now nice and toasty. Looks like a trip up north for the ole tranny.
>
> One question: those who have had transformers re-wound, do you have them re-wound to today's line voltages? or keep 'em to the old spec...mine L/V is in the 125v range.
> Tnx for all the suggestions...73 de Bill K4JYS
>
> ----- Original Message -----
> From: "Bill Stewart"<cwopr at embarqmail.com>
> To: "heathkit"<heathkit at mailman.qth.net>
> Sent: Monday, January 30, 2012 2:55:09 PM
> Subject: [Heathkit] DX-40 Pwr Xfmr
>
>
>
>
>
> Good afternoon:
>
> My trusted DX-40 is blowing its fuse. After some initial checks, I have disconnected the HV leads and made the following measurements: Total HV winding resistance: 312 ohms
>
> Outside-to-ct: 181ohms/344 vac....
>
> Outside-to-ct: 131 ohms/274 vac. The ac measurements are made with 60vac at the plug.
>
> The xfmr gets warm even tho the on time is short.
>
>
>
> Would ya say this resistance/ac voltage imbalance would indicate a tranny problem?
>
> Thanks, 73 de Bill K4JYS
>
>