Johnson Valiant oops

Discussion in 'Technical' started by WB6KWT, Jul 27, 2017.

  1. WB6KWT

    WB6KWT Member

    I was attempting to change my disfigured front panel on the valiant, everything was going great until I took that large VFO nut off. Right away I noticed movement that I thought was unusual. I had read many posts about being careful of the phonelic coupler and as pulled the panel off, the VFO coupler fell to the bottom of the VFO enclosure, yep it broke. I wonder if that is the end of my Valiant, is there any way to repair the thing of maybe a way to replace the phonelic coupler with something else?

    Your thoughts please.

    Thank you,

    Bob - wb6kwt
     
  2. W5HRO

    W5HRO Administrator

    I' trying to remember because it's been so many years, but does it look like this?

    coupler_orig.jpg

    vfo_coupler.jpg

    If so those repair kits above were on eBay once upon a time, but that was a long ago. You can always just make one. It's really not that hard. If the stock one that broke has rivets, just drill them out, find a piece of similar material and cut it the same size. Then drill the 4 holes in the corners and use screws.
    .
     
  3. W6MQI

    W6MQI Member

    Don't see them anymore on Ebay I also broke mine on my Ranger ended up having to rebuild it myself. The real trick to putting it back together is keeping the whole assembly concentric so things don't wobble when turned. Get yourself some thin G10 or similar material slide the whole assembly onto a 1/4" rod to keep things concentric while bolting or pop riveting back together. Just watch out the flanges on the coupler are real soft and will twist out of shape if you need to increase the hole size. It is possible to fix just need a little patience good luck Bob.

    Dave
     
  4. WB6KWT

    WB6KWT Member

    Thanks for the response. I haven't been able to get the VFO "chamber" opened up but from what I can see it does look like that but a darker color. I'll get back to it tomorrow and see how it goes.

    Bob
     
  5. W6MQI

    W6MQI Member

  6. WB6KWT

    WB6KWT Member

    Thanks, I've been emailing with that fellow, trying to set up a time to pick it up. He lives in Stockton and I'm in Tracy but so far can't get a time. That one is in really poor condition but there may be some parts of use.

    Bob
     
  7. W6MQI

    W6MQI Member

    Good luck Bob

    73, Dave
     
  8. WB6KWT

    WB6KWT Member

    Dave, you suggest sliding the whole assembly on to a 1/4" rod, this suggests I need to drill a 1/4" whole in the center of the material, is this correct? I'm still trying to get the shield off the VFO, I've found most of the screws but at least one is hiding from me.

    Bob
     
  9. W6MQI

    W6MQI Member

    Yes detach the coupler from the broken insulator I think there were pop rivets that need drilling out, fabricate a new insulator piece, drill a 1/4" hole in the center of the new insulator then slide everything together onto the shaft. Now you can clamp things together and drill the holes in the coupler flanges, and through the insulating material all at the same time hopefully everything will stay put while drilling.

    Valiant coupler.jpg
     
  10. WB6KWT

    WB6KWT Member

    Thanks Dave, thought so but just wanted to make sure. Still fighting with the enclosure, I believe one of the screws is seized, I can't get it to move even though I have the nut off. I put a bit of liquid wrench on it and will check it tomorrow. Thanks for the diagram.
     
  11. WB6KWT

    WB6KWT Member

    Okay, I found the nut I missed but I can't see anyway I can reach it. It's the one on the bottom left side, of the VFO enclosure, and under the band switch shield. I sure don't want to remove the band switch shaft and all that is connected to it. I don't know where to go from here, any suggestions?
     
  12. W6MQI

    W6MQI Member

    Hmm... All the screws on the outside of the VFO box are self tapers the only nuts I remember are connected to the threaded mounting studs. The nuts on the threaded studs should all be accessible from the bottom side with a 5/16 nut driver. Once the nuts on the bottom side are removed its just a matter of wiggling the VFO box around enough to lift it off the chassis. Sometimes a screw driver is needed to pry between the inside of the VFO box, and the Bakelite shelf to get things to slide by while lifting up to remove the VFO box from the chassis its a real tight fit.

    P.S. do you have a Johnson assembly manual?
     
  13. W6MQI

    W6MQI Member

    Okay here's a picture of the nuts on the bottom side that you should remove to lift the VFO box off.

    VFO screws.jpg
     
  14. WB6KWT

    WB6KWT Member

    Dave, the threaded studs are the ones I'm talking about. All are out except the one I talked about, I'll see if I can post a photo. I do have a copy of the manual, didn't think about looking in there, it's one of those the SK fellow was selling.
     
  15. WB6KWT

    WB6KWT Member

    Oh, just got the picture, thanks that will help.
     
  16. W5HRO

    W5HRO Administrator

    Have you also read this, not the exact info you are looking for, but its related. I never did this mod to mine, but it would probably really help.

    https://www.w8ji.com/johnson_vfo_chirp_jump.htm

    I assume you are getting in there to replace the bad 18K screen dropping resistor and if so relocate it outside of the VFO compartment under the chassis.
    .
     

    Attached Files:

  17. W6MQI

    W6MQI Member

    Brian,
    He's having to replace the VFO shaft coupler which is broken which requires removal of the VFO can A major PIA. Agree since he's in there might as well replace, and move that 18k resistor. Wonder if any other mods have been done like recapping?
     
  18. W5HRO

    W5HRO Administrator

    There's a lot of people who also like to relocate the 0A2 tube or just use a zener there instead to remove heat, but I'm not sure it’s worth it. I would defiantly replace both of the tubes though just to be safe since he's taking it apart. It would suck if the 6AU6's filament burned out down the road or the 0A2 went bad. Then he would have to take the thing apart again.

    vfo.jpg
    .
     
  19. WB6KWT

    WB6KWT Member

    Thanks for the suggestion. This Valiant has had a rough life but the fellow I got it from had gone through the whole transmitter. He moved R3 to the outside of the enclosure, which I know others have done and still others say change it and leave it in there. I have the manual he had and he marked every resistor and cap that he replaced along with the tubes. The high voltage tubes have been changed to 3B28's. I'm still struggling with getting to the coupler, even though Dave sent that very nice picture. I'm going to see if I can get a good clear picture of the bottom and post it, maybe you guys can see something I'm missing. I've got all the screws off the studs but the enclosure will not budge on the left side. I have the side cover off hoping to see if something else is holding it.
    Picture forth coming.
     
  20. W6MQI

    W6MQI Member

    Bob,
    I think there is 2 nuts underneath the shield covering the rotary switch remove the shield and have a look.
     
  21. WB6KWT

    WB6KWT Member

    I'm trying to send a picture but it's not going. What size image is possible?
     
  22. W5HRO

    W5HRO Administrator

    3500px x 3500px
    .
     
  23. W6MQI

    W6MQI Member

    Bob,
    Click on (upload a file) find the folder where your picture is, the double click on the picture and it will automatically upload from there.
     
  24. WB6KWT

    WB6KWT Member

     
  25. WB6KWT

    WB6KWT Member

    Okay, let's try this again.

    My_Valiant2.jpg