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Diamond SX-600 - shorted output.

Discussion in 'General Technical Questions and Answers' started by KD8UFC, Apr 1, 2013.

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  1. KD8UFC

    KD8UFC Guest

    It must be impossible to receive two brand new pieces of equipment, from two dealers, on the same day,
    and find the IC-7200, AND the SX-600, both suffering from shorted coaxial outputs. But it happened to me
    this past Friday.

    On the SX-600 SWR meter, there are two output circuits. One is for 1.8 - 160 MHz, and the other is for
    140 - 525 Mhz.
    Each output uses two so-239 connectors, one for the xmtr and one for the antenna.
    The connectors for the 140 - 525 MHz seem to be just fine.
    But the other two (1.8 - 160 MHz) are shorted! With the unit completely unpowered, and straight out of
    the box, the pl-259 connectors are shorted between the center holes and the outer threads. Also, the one
    connector is shorted to the other connector. Have you ever heard of this happening? Does anybody check their
    work anymore, before signing the little inspector sticker? Expense isn't bad enough, this is going to take time
    to correct... unless the dealer (well known) just exchanges it for a working unit. But I doubt that will happen.
    They have my money and they are on the air. I don't have my money, nor any more where that came from,
    and I'm OFF the air. A very unhappy Easter surprise for me.

    With your greater experience, does this seem to be a common problem? Can I fix this without nullifying my
    warranty? Am I just missing something, here? I'd rather repair it myself, but unless it's a cockroach caught up
    in the wiring, I probably won't be able to. I've read about a diode-bridge and other circuitry that isn't very
    serviceable, nor cheap to replace.

    I don't know if I need a technician, or a psychiatrist, at this point. But I thought I'd check with my ham friends,
    first. The best I can do now is sit on top of my chimney and holler out a "CQ". (Hmmm... might work...)

    Bob KD8UFC
  2. W9GB

    W9GB Ham Member QRZ Page

    Contact dealers, return purchases for working equipment. That is your right -- use it !
  3. K9ZMD

    K9ZMD Subscriber QRZ Page

    Interesting. What symptoms clued you that there was a problem, and how did you ultimately determine that the coax jacks were shorted?
  4. KD8UFC

    KD8UFC Guest

    With the IC-7200, you attach an antenna, put it in "TTY" mode, and key the microphone. The SWR meter in the window displays the SWR.
    Well, the meter showed "infinite". (I did not keep it that way for any length of time) Sometimes, the xcvr would simply shut down, with the
    snapping sound of a relay. Well, after some thinking and much reading, it seemed that the antenna must have been shorted. So, I tested the
    coax, the dipole legs, and looked over the feed point. There, it did read a dead-short. But with the coax disconnected from the xcvr, the short
    At that point, I attached the coax to the SX-600 swr meter, to see if the antenna would again show a short. And it did. Disconnected, it was
    again OK. So, that's when I put the ohm meter on the coax jacks, to see if maybe the unit was shorted internally. That's how I found the shorted
    connectors on the SX-600. But only on the HF side. The UHF connectors read OK.
    The xcvr's connector shows a reading of 30k, between the hole and the outer threads. The receiver works, though, so I'm assuming that in
    shutting down, something becomes grounded in the output circuitry. Then the connector appears to be shorted. Or maybe it is, I don't know.
    I looked a schematic and it's more complicated than a map of Chicago. I can't interpret that. So, I'm left without the paddle, AND the canoe!

    It isn't easy putting down a thousand bucks, or even hundreds, for every little thing that must be had. I seem to remember a day when people
    actually double-checked their work before clocking out from the factory. If they didn't, someone else did. Today, hardly anyone does - and it seems
    like no one really gives a crap. But someone put the final OK on my transceiver and the swr meter. And it was not working at that time.
    Forgive me for sounding mean, but I hope his boss gets two flat tires on his way to the bank.
    Oh, I didn't mention my keyer that has a screwed up timer, so the dashes are too short. That's OK, though. I'm learning to use a sideswiper key that
    I'm building myself, with a hacksaw blade. Sideswipers are better, anyway. (If I only had a transmitter) And I apologize for the rant.

    Thanks, Gary.
  5. KD8UFC

    KD8UFC Guest

    Of course, I will exercise my rights - starting today. But while I'm doing that, and while the sellers are exercising their rights to stall, and just say "no", I am the one who is left without
    my equipment - and without my money. They have both. With 700,000+ licensed radio hams in this country, how can this sort of thing happen to us, over and over again. I'm getting
    to be an old man, now; and a few years ago, I came back from a diagnosis of DOA and sudden cardiac death, and I lost sight of the fun of fighting for things that ought to be mine. It's
    pretty much over for me, now. I just got my little grandson all interested in this ham business and I don't want to see him being disappointed over and over again, too. You're right, and
    I agree - it's my right to contact dealers, and return purchases, and lose time on the phone, and wait for responses, and be frustrated, and wear out my heart muscle. But is that what
    ham radio is all about? This isn't what I read in those long-ago ARRL books.
    I would never have even known about electronics if not for the time, and kind-hearted attention, of a few "old guys" who stopped to help and encourage a 12 year old kid, who had little
    to start with. I guess they're all gone, now. But still, somebody assembled that ICOM xcvr, and the Diamond swr meter. Somebody put his final "OK" on the little inspection sticker, too.
    But the faulty equipment that was soon to become mine, wasn't working any better at that time, either. Now, I'm stuck with it and they're not. They have my money (a lot of it) and I don't.
    If this were only about rights, I guess I'd be more excited about the coming time and frustration that awaits me. But I thought I had a right to receive what was offered to me, and promised
    to me. I really am feeling way too old for any more of this crap. When the big hamvention-circus comes here to Dayton in a few more weeks, I'd like to see everyone stay home for the weekend. Let the ICOM giants know how it feels to wait, and wait, for what never comes. I'll bet after that kind of expensive week-end, they'd be more a little more considerate of the hams who support them. Maybe then when they say, "This rig's OK", it really will be OK. Then I could buy it and be as happy as a little devil in hell. And I'd have spent this holiday weekend saying, "CQ contest... CQ contest... CQ contest.", instead of saying all those terrible things that I can't repeat in this forum.
    It's about intent, and integrity, and an "honest deal", isn't it?
    It's also about us sharing knowledge, and finding solutions together, for the benefit of all of us. It seems there is less and less of that, and more of my kind of long-winded ranting. I'd rather
    get back to the solution finding - and I will, just as soon as I have a signal radiating from my shack.

    Thanks for your response, my friend.
  6. M0GVZ

    M0GVZ Ham Member QRZ Page

    Sorry but there is nothing wrong with your SX600 meter. I've just checked my perfectly working one and it shows the same.

    The problem is what you are forgetting is that just because something appears to be a dead short at DC doesn't mean it appears as a dead short to AC/RF. A 4:1 balun appears as a dead short to DC but isn't to AC/RF - many antennas with matching sections are similar - dead short if tested with a multimeter.

    I seem to remember a day when people actually learned the subject instead of memorising the answers of the question pool. Had you learned the subject you'd know that just testing radio equipment with DC testing methods doesn't always give the correct result.
  7. M0GVZ

    M0GVZ Ham Member QRZ Page

    And they will exercise their rights to make you look like a fool. I strongly suggest you test the SX600 with a dummy load plugged directly into the meter.
  8. KE3WD

    KE3WD Ham Member QRZ Page

    DC continuity checks, such as with ohmmeter, mean NOTHING to the AC of RF.

    There could be an RF coil from center to ground, which will measure close to zero ohms at DC, but will be an entirely different impedance at the frequencies which the device is designed to operate.

    Designing like that allows for the bleed off of static DC charges that otherwise would exhibit as noise in your receive and possibly transmit signal. It is intentional, and a good thing.

    There is likely nothing at all wrong with your two pieces of equipment.

  9. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Don't have an SX-600 here to check, but most "rigs" like HF transceivers will show a DC short circuit across the antenna connector, that's pretty normal. Some speciality VHF rigs don't, because they impose DC voltage on the antenna line to power an optional remote mast-head preamplifier, so a short circuit across the antenna won't work. But HF rigs don't do that, and mine all show a DC short across the antenna connector. Normal.
  10. K8JD

    K8JD Ham Member QRZ Page

    If you read a short on the connector going to your antenna, check that first.
    if it is a "regular dipole" without BalUns and other exotic hardware, it should read open (near infinite ohms) across the radio end connector..If it is a multibander, who knows what hardware is used to acomplish that .A DC short is OK on many multiband manufactured "dipoles"
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