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WANTED:Power Transformer for 51J 4

Discussion in '"Boat Anchor" & Classic Equipment' started by K5HFG, Jul 2, 2018.

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  1. K5HFG

    K5HFG Ham Member QRZ Page

    Collins no. 672 0575 00
    If you have one you do not need, contact me with price.
    TNX, Don K5HFG
  2. K5HFG

    K5HFG Ham Member QRZ Page

    Still searching. I really do not want to stick a different style replacement in the receiver.
    I know there is an original out there.
  3. W5INC

    W5INC XML Subscriber QRZ Page

    Try Gary, WZ1M up yonder in Maine. Gary rebuilds the original unit for about 200.00 and it should go right in again with no problems. For BAs Xformers which are now getting harder and harder to find, getting your old unit rewound, might just be the best way of restoring your 51J-4 unit. Good Luck on your project. Let us know how it turns out for you. :)

    TRS Transformer Rewinding Service 478 Forest ave. Orono, Maine 04473 Tel: 207-942-5745. Email:
  4. K5HFG

    K5HFG Ham Member QRZ Page

    Thanks for the info. BTW, that is a handsome dog. Reminds me of my old Nick, many years ago. He hunted with me. We climbed a lot of hills.
    TNX, Don
  5. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    The power transformers from any of the 75A- receivers or the 51J- / R-388 receivers should work fine and fit the holes in the chassis. The only thing is that most 51J-4 / R-388A receivers have cube shaped power transformers and the other transformers have the "traditional" shaped housings and the 51J-4 / R-388A transformer is rated from 45 Hz to 70 Hz whereas the other power transformers are 50 Hz / 60 Hz. The voltages, and current requirements are, basically, the same. For normal operation, any of those transformers will work fine and not really look out of place.

    Glen, K9STH
  6. K5HFG

    K5HFG Ham Member QRZ Page

    Thanks Mike and Glen. I have a 75A2 that I have not got around to restoring and I had compared the transformers. Decided to keep the 51J4 original. Took Mike's advice and contacted Gary WZ1M and he will rewind the transformer for me. He will update the primary also. The receiver works fine but the transformer started getting hot and was seeping. So off it goes for a rewind and primary update and all will be well. Thanks for your replys.
    73, Don K5HFG
  7. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page


    You have replaced the electrolytic capacitors and the "black beauty" / paper capacitors in the 51J-4. If not, before you go through the process of getting the transformer rewound, do so. That may take care of the heating problems with the transformer. Those capacitors are going to be leaky and, even with the rewound transformer, that transformer is going to overheat as well. In addition, the silver-mica capacitors may also be leaky.

    With any "boat anchor" equipment, and especially in any of the Collins equipment, replacing all of the paper capacitors and electrolytic capacitors is automatic. The "black beauty" and the "brown beauty" paper capacitors are notorious for becoming leaky and the electrolytic capacitors are almost always bad as well.

    The silver-mica capacitors are now going bad on a regular basis with migration of the silver between the plates within the capacitor.

    Go to

    for the list of capacitors that are very problematic in the 75A-4 receivers. Then, compare the location of those capacitors in the 75A-4 with their location in the 51J-4. The designators are going to be different but the capacitors are in the same electrical location in the respective receivers. For the vast majority of those who routinely work on the Collins equipment, replacing all the paper capacitors, electrolytic capacitors, and silver-mica capacitors is automatic. Yes, there might be individual components that are still fully functional. However, not replacing those components is a "time bomb" waiting to go off and, when the component does fail, it often takes out other, much more expensive, components along with the original component.

    Glen, K9STH

  8. W5INC

    W5INC XML Subscriber QRZ Page

    The Walker hound, Barney on my QSL card/ Zed page has passed into the cornfield, from bone cancer. Barney was a great dog and could track anything or anybody once he got the scent. He was the runt of the litter and the breeders wanted to send him packing because of it. I somehow convinced them it was in their best interest to let me have the dog and it was 1 of the better decisions I have made. It was a very tough day when I had to put him down. Hopefully, he will be at the Rainbow Bridge, along with his other pack mates, that I have been fortunate enough to share Life with, when the time comes. :)

    What was the life expectancy of these Xformers to begin with? Do they last longer when not being used for 20 to 30 years and then put back into service? Do they last longer if they are used on a continuing basis, not left to sit idle for long periods of a time? I really don't know the answer to that question, maybe someone can chime in on this.

    If you are going to keep the J-4 Mr. Don, getting the Xformer rebuilt, with updated primaries to handle today's line voltages, is probably the best way of going about it. You know for sure that the Xformer is working 100% correctly and going to fit right back into the rig, with no wiring mods needed. Gary rebuilds a lot bigger transformers then these small units. Dismantling a Xformer correctly, is just as important as rebuilding it correctly. An acquired skill to be sure and 1 I don't have in my quiver. So Gary will get my business, when I need an Xformer to be rewound here in the near future. ;)
  9. K5HFG

    K5HFG Ham Member QRZ Page

    I have followed your advice for years. All caps have been replaced and this receiver has been operational and a daily used dependable rig for several years. I noticed some time ago that it was getting a bit warmer after an evening of SWLing so I kept an eye on it. Last week it began to smell funny so I shut it down an discovered some black oily liquid seeping out from under the transformer and the transformer was hot to the touch. So here we are. I am going to have it rewound as soon as I extricate it from the chassis. Looks like a several hour job. I think this is the best approach as everything else is working FB. As always I appreciate your replies.

    So sorry to hear of Barney's passing. I was 18 when Nick passed all those years ago and I still think about him from time to time. Seeing your picture sent me reminiscing and I could still picture Nick running zigzag through a grass field on the hunt. Well, that was fifty years ago and now I have my favorite receiver down but not out. Thanks for your replies as well, will let y'all know how this plays out.
    73, Don K5HFG
  10. WB2GCR

    WB2GCR Ham Member QRZ Page

    You could un-pot the transformer.
    Then install a replacement, in the can.
    Keep the black goo from the un-potting and re-pot... how to do that is out on the web.

    I have replaced the transformers on both the R-388 and the 75A-2. Not the same spec exactly, iirc.

    There are several "stock" numbers that are Stancor or Thordarson types.
    They can be found on epay if you are reasonably patient.
    I found them.
    The best one(s) are listed as "TV Replacement"
    P-8176 Stancor is a good candidate.

    Also the early R-388s did NOT have potted transformers. I have one. :D

    I suspect that these transformers are in reality not "specials" and were "off- the-shelf"
    and bought with Collins numbers on the shell, or later the same iron was potted for Collins.


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