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Dentron Super Tuner--where to get parts?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K3RW, Jan 27, 2018.

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  1. K3RW

    K3RW Premium Subscriber QRZ Page

    I have a Dentron Super Tuner (not the Super Super) that I was recently given. I opened it up and the plexiglass-looking insulators under both variable capacitors was cracked, some of it shattered. Sounded like a box of broken glass.

    I've tried to make my own insulator but couldn't quite get the right height/shape for it since so much of it was broken. I tried tracing the capacitor frame and using wood just as a template to cut out some thicker plexi stuff later. But not happy with the result so far. The capacitor shaft grinds and binds a bit at the slightest off angle. Not sure if that could cause arcing.

    Now there might be a place where I can just order two of them. Anyone know where I might find them?
     
  2. KB3UWC

    KB3UWC Premium Subscriber QRZ Page

    I will be watching this thread. I have a Dentron with this problem. I think mine was dropped in shipping at some point, but i got it for free.
    Steve KB3UWC
     
  3. AK5B

    AK5B Ham Member QRZ Page

    I used to have a DST when I lived in KH6 and I had a problem with deteriorating plastic/ bakelite shaft couplers. A W5 ham over in Louisiana machined some new ones out of acetal or some other durable type of plastic for me at minimal cost. If I can ever recall his callsign I'll come back here and post another reply (might be in my old emails). The new couplings were a considerable improvement over stock.

    As for the insulating sheet underneath I would think that Lexan or even a Wal-Mart cutting board could be cut to size as a replacement unless I'm missing something here.

    73,

    Jeff

    UPDATE: Paul, AE5JU in Morgan City, LA is the fellow who made my couplings. Turns out that they were made out of easy-to-obtain nylon bushings that were simply tapped for the shaft set screws. Hope this helps!
     
    Last edited: Jan 27, 2018
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  4. K3RW

    K3RW Premium Subscriber QRZ Page

    :)
     
  5. WB9OST

    WB9OST Ham Member QRZ Page

    I to had the problem with the insulators. I made new ones from 1/2" PVC water pipe and some heat.
    Start with 2 pcs of scrap wood, (1x3) several inches longer than the old insulators. Then cut some more scrap to 1/2" thick and attach to one of the boards cut earlier along the bottom. Use 2 short pcs
    mounted at the ends of the long bottom piece to form a channel.
    You now have a jig to form the PVC between the 2 boards the length and width of the old insulators.
    Now the heat part. Cut the PVC longer than the insulator you are replacing but that will fit into the jig.
    I used an old toaster oven to heat the PVC until it was very soft. Use gloves to insert it into the jig and cover it with the second piece of scrap lumber. Put the jig into a vise or some type of clamp and let it cool.
    You should now have a flattened piece of PVC 1/2" thick and 3/4 to 1" wide. This is wider than the original part but there is lots of room to mount it under the tuning cap.
    Now cut to length and drill mounting holes for the cap and the chassis. Counter bore the opposite side of the holes with a drill that will pass the head of the screw you are using to mount everything.
    I have been using the tuner for about 8 months at about 600 watts with no problems at all.
    Just some scrap parts and a little time and the satisfaction that it works.
    73 Lee
     
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  6. AE5JU

    AE5JU Ham Member QRZ Page

    I've been asked about making the insulators under the capacitors for the Dentron Super Tuner. I've never made any, but if someone can send me a good drawing with measurements perhaps I can turn a few. What I have made for tuners are the insulated shafts and couplings as mentioned by Jeff NH7RO above. These were quite easy to make. I used nylon spacers from True Value Hardware, I think 5/8" or 3/4" OD x 1/4" ID (the shaft size) x 1" long. I drilled holes and tapped for 8-32 set screws. And I obtained some 1/4" nylon or acetyl rod ("Delrin") for the shaft itself. If someone could supply me with an insulator, I would be glad to turn (on a lathe) some in return. Once I had measurements, I could make more.
     
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  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    A 3D printer can be handy to have. :)
     
  8. WA4SIX

    WA4SIX Ham Member QRZ Page

    Cutting board material is simple.
    I am guessing that 1/2" is about what is needed?
    If so, a counterbore, so flathead is about 1/4 deep & use a bung cutter, or UHMMW rod to bung (Great insulator & probably will not arc over, easily.

    Ed
     
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  9. AK5B

    AK5B Ham Member QRZ Page

    IIRC, those white Walmart cutting boards are next in line after Teflon, acetal, air and a vacuum. Talk about bang for the buck!
     
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  10. KA9JLM

    KA9JLM Ham Member QRZ Page

    Getting material at the local zoo just don't sound right. :rolleyes:
     
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