What could cause coax to fry?

Discussion in 'DIRECTV General Discussion' started by rking5150, Aug 3, 2009.

  1. Aug 3, 2009 #1 of 14

    rking5150 AllStar

    Jul 31, 2008
    I've got a slimline-3 on my roof co-located with a powered multi-switch, and four lines run down the side of my house and then enter the basement (the other 2 lines drop right through the ridgevent in my attic to get to the upstairs). Anyway, on my HR-20 and HR-21 I started receiving a guide not updating message every few hours, so I ran a signal meter test, and, for the 101, I received a signal on every other entry (e.g., 0 87 0 95 0 93 etc.) That didn't seem right, although I was getting a picture.

    I ran a system setup, and it failed because it was not receiving a satellite signal. So, I went outside to look at the wiring.

    I recently had my roof replaced, and when the DTV tech came out, he shortented the cable runs from the roof to the house by taking out the slack and putting in connectors. When I touched one of the 4 connectors, it almost burnt my hand -- it was very hot. I grabbed some wrenches, and when I took the two ends off of the connector, the coax wire was literally burnt to a crisp.

    The other wires are fine.

    I've got DTV coming out on Wed to check this out, but anyone have any ideas what could have caused this? A bad ground in the coax? A problem with the power for the multi-switch?

    I'm just trying to avoid having to have them come out again if they don't figure out the problem.

  2. Aug 3, 2009 #2 of 14

    Rakul Slacker

    Sep 3, 2007
    How long has this set up been in place? If you have a powered multiswitch it could have been an improperr connection (ground touching line maybe)
  3. Aug 3, 2009 #3 of 14

    rking5150 AllStar

    Jul 31, 2008
    Before the roof replacement, I had it set up this way for 3 + years. In its current configuration, it's been about 45 days (which puts me in the warranty!).

    I have a feeling that there's some sort of grounding issue. Probably just a matter of time before the switch tries to ground through one of the remaining 3 lines now.

    Does DTV have a nonpowered multiswitch for use with the Slimline-3?
  4. Aug 3, 2009 #4 of 14

    paulman182 Hall Of Fame

    Aug 4, 2006
    I'd say the tech shorted the shield and center conductor at the connector when he put it on, or left a stray strand of braid loose in the connector and it shorted later.
  5. Aug 3, 2009 #5 of 14

    netraa Godfather

    Mar 27, 2007
    or, the powered switch is going out and allowing power to leak through 1 of the dish leads.

    or, the LNB is going out and shorting out through that particular lead.

    i've personally seen both issues happen.
  6. Aug 4, 2009 #6 of 14

    boba Hall Of Fame

    May 23, 2003
    Are you sure you have a powered multiswitch? The WB68 isn't powered the WB16 is powered but it sounds like you only have 6 outputs.

    Corrosion from water getting into the fittings can cause resistance which will cause heating. Your findings when you loosened the fittings sounds like water getting into the splices.
  7. Aug 4, 2009 #7 of 14

    rking5150 AllStar

    Jul 31, 2008
    Yup. I have a powered multiswitch. It is from the original install -- about 3 years ago when I had a 5 LNB dish.

    Its way on the top of the roof, and I have not personally seen it, but the installer told me (3 years ago) that it had 6 outputs.

    Personally, I would perfer to drop another 2 lines into the attic and add another multiswitch there....
  8. Aug 4, 2009 #8 of 14

    harsh Beware the Attack Basset

    Jun 14, 2003
    Salem, OR
    There is only one powered multiswitch that is compatible with the Ka/Ku dishes and it has 16 outputs. If you don't have a Zinwell WB616, you have a non-powered Zinwell WB68. It doesn't really matter what (or what you thought) the tech said.

    I'd go with paulman182's suggestion of a bad termination.
  9. Aug 4, 2009 #9 of 14

    rking5150 AllStar

    Jul 31, 2008
    Thanks. It is, however, a powered MS -- I've got the power source in my attic and the coax running to it, and I know that it doesn't have more than 6 outputs since I asked to have another line dropped through the attic, and the tech said that would require a new switch.

    I do have a non-powered Zinwell in my basement taking the 4 lines there and providing 6 outputs.

    I agree re the water issue. I was going to add new connectors myself, but I might as well wait for the DTV guy to come out and verify that it isn't something more serious, especially since I'm still under warranty from the reinstall.

    I'm also going to wrap the connectors in electrical tape after he fixes them.

    Thanks everyone.
  10. harsh

    harsh Beware the Attack Basset

    Jun 14, 2003
    Salem, OR
    It sounds like someone has installed a "signal locker" in the system. I can't imagine why someone would cascade two multiswitches to serve only six tuners when a single non-powered multiswitch should have accomplished the same goal with two tuners worth of capacity to spare.

    Am I correct in assuming that you have six or fewer tuners?

    Having more switchgear than necessary isn't typically a good thing as it increases the number of possible failure points without providing significant benefit.
  11. rking5150

    rking5150 AllStar

    Jul 31, 2008
    I have 7 tuners (2 HD-DVRs, 3 SD) in the house. It's a strange configuration since the dish was installed pre-HD with 5 SD receivers.

    Here's what I have:

    2 lines through the attic to two SD receivers

    4 lines down the side of the house to a junction box going to a 4x6 mutliswitch -- to one SD receiver, HR-21 and HR-20.
  12. carl6

    carl6 Moderator Staff Member DBSTalk Club

    Nov 15, 2005
    Seattle, WA
    For an HD installation from a Slimline dish, you appear to have more than one problem. If what is in the attic is indeed a multiswitch, and it is not a WB68 or WB616, then that's your first problem. I'm not aware of a 4x6 multiswitch, they will typically be 4x4 or 4x8. Let's assume the 4x6 you refer to is a 4x8, and it's a WB68.

    The hot connector with the burnt coax probably had a ground shorted to the center conductor in it (improperly installed connector). That could easily cause a lot of current flow which would produce both the heat and the guide issues.

    Whatever the tech does when he comes out, after he is done you want to check (1) that you are getting all of the channels you are supposed to be getting and (2) all of the applicable test channels work properly.

    480 - 103 odd
    481 - 103 even
    490 - 101 odd
    491 - 101 even
    492 - 119 odd (not applicable if you have a Slimline 3 LNB)
    493 - 119 even (not applicable if you have a Slimline 3 LNB)
    494 - 110 even (not applicable if you have a Slimline 3 LNB)
  13. rking5150

    rking5150 AllStar

    Jul 31, 2008
    Thanks. I have a feeling that the problem stems from water getting into the connetor -- the tech put the connector on the wire on the ground by a downspout -- not the best choice. Anyway, I'll seal that puppy up really well after he puts it back together.

    The switch is actually mounted outside by the dish. It's secured to the dish support. When they go back up again, I'll ask again to have two additional lines dropped into the attic so I can put a multiswitch there and put a HD-DVR on the second floor of the house. I hope you're right -- if you are, then 2 techs have lied to me to avoid doing that.

    Thanks again.
  14. joe diamond

    joe diamond Hall Of Fame

    Feb 28, 2007
    If it has six "outputs" it was installed backwards.

    Shorted connector seems right. Check every fitting on the line and examine the multiswitch.


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