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Advanced Troubleshooting Help Needed

Discussion in 'DIRECTV General Discussion' started by mmanna, Aug 24, 2008.

  1. mmanna

    mmanna New Member

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    Sep 19, 2007
    I am pretty sure I have a signal issue somewhere on the outside, and am looking for some advice. Here's my explanation of the situation:

    I've had D* for several years, with no signal issues until I got the HR20 and HD Locals nearly 2 years ago. Since my prior receiver (TiVo) had 2 tuners, I already had 2 coax lines from the dish, so wiring is the same and is several years old. I think I recall D* installing a new dish just before or after I got the HR20. Ever since getting HR20 and HD, I have had pixelation / green blocks / audio cut-outs / etc. on an almost daily basis, but on my LOCAL channels only. In the past 2 years, I think D* has replaced my HR20 three times and it's made no difference.

    About 2 weeks ago, I started having problems listening to XM Radio (ch 816) on my HR20. Some days it would work fine, and other days it would cut in and out and make popping/clicking noises. Whenever this started, I would go to another music channel and all others that I listen to work fine. When 816 started acting up, the TV would say "Searching for Signal on In 2" (input 2, I assume?).

    This new problem has lead me to a renewed troubleshooting effort. I called D* tech support Friday night and went through some troubleshooting. The rep said all of the signal levels on all satellited/transponders on the "View Signal Strength" looked fine (most were 95% or higher, a few were in the high 80's)

    Now here's where it gets bizarre and confusing to me ... While on the phone with D* tech supp rep, my problem with ch 816 got so bad that it steadily remained on "searching for signal on in 2" at which point the rep had me go into my spare room and try ch 816 on my old non-hd receiver. The old receiver was unplugged at the time due to recent storms, and when I plugged it in and tuned to ch 816, the signal came back immediately on my HR20. The rep said it was just a coincidence, but I insisted it wasn't and was able to consistently reproduce this three times in a row. As soon as I unplugged the power from my old receiver, the HR20 lost it's signal for ch 816, and as soon as I plugged the old receiver back in and tuned to ch 816, 816 would come back on the HR20. As a computer tech, I'm fairly good at troubleshooting, but this has me totally stumped. From my basic understanding of satellite signals, there should be no way for any of my receivers to "interfere" with each other. There are no splitters, just three direct lines coming from my dish, through a quad grounding block, with two of the lines going to my hr20, and the other line going to my spare/old receiver.

    Also of note ... the grounding block is not actually grounded to anything. I'm guessing that the purpose of the grounding block is to help protect against lightning and such. Can anyone tell me I'm incorrect and that the grounding is necessary for a reliable signal? D* performed the initial installation, so if this lack of grounding is the cause of all my problems, I'm going to be a bit annoyed!

    The D* rep had me hold the right arrow and press the ACTIVE button on the front of my receiver which brought up the diagnostics page showing high 90's for Tuners 1 and 3, and something low in the 50's or 60's for Tuner 2.(this was on Friday night).

    Tonight, I disconnected, inspected, and reconnected ALL coax connectors between my dish and HR20 receiver, including those at the grounding block and BBC's and didn't see any corroded or broken connections. I checked my levels (from the diagnostics screen mentioned above) before AND after doing this. Before doing it, the 3 levels were 96/89/90 (with the spare receiver unplugged).
    After doing it, they were 96/94/90. Now, about 2 hours later, they are all fluctuating in the high 90's regardless of if I plug in the old receiver or unplug it.

    Any input and/or additional troubleshooting ideas would be greatly appreciated! I'm starting to get excited that the resolution of this new problem may also fix my long-term problem I've been having with my HD locals.

    Marc
     
  2. evan_s

    evan_s Hall Of Fame

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    Mar 3, 2008
    It sounds to me like you might have a problem with power loss across cables your HR20 is connected to. Tuning a second receiver to that same channel is adding power to that particular lnb. If it's reasonably easy to do I'd replace the cables with good quality solid copper core cable. If thats not practical you could use a powered switch like http://www.solidsignal.com/prod_display.asp?prod=WB616 or a power inserter and regular multiswitch like http://www.solidsignal.com/prod_display.asp?PROD=HRPID1422 & http://www.solidsignal.com/prod_display.asp?prod=WB68
     
  3. eakes

    eakes Godfather

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    Sep 21, 2007
    This could be a coax problem or it could be a LNB problem. There have been several threads here in the past week or so of intermittent pixelation problems being solved by replacing the LNB.

    I would replace the coax (all the way to the LNB) and if that didn't solve the problem, I would replace the dish.
     
  4. joe diamond

    joe diamond Hall Of Fame

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    Feb 28, 2007
    The LNB is the common point to all the receivers. Try switching the leads around and see if you can make the problem move from one receiver to another........then replacing the LNB is next.

    Also, those quad ground blocks are buggy. I've had problems with them. Try using barrels to by pass them one at a time.

    Joe
     
  5. techrep

    techrep Hall Of Fame

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    Sep 15, 2007
    [QUOTEAlso of note ... the grounding block is not actually grounded to anything. I'm guessing that the purpose of the grounding block is to help protect against lightning and such. Can anyone tell me I'm incorrect and that the grounding is necessary for a reliable signal? D* performed the initial installation, so if this lack of grounding is the cause of all my problems, I'm going to be a bit annoyed!/QUOTE]

    The absence of grounding will not affect/effect your signal. Improper grounding can.
     
  6. K4SMX

    K4SMX Hall Of Fame

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    May 19, 2007
    How long are your total cable runs? We can suspect that at least some of your cabling from the dish is from the pre-HD installation, and perhaps the older cable is connected to the tuner 2 input of your HR.

    I think an interesting experiment before replacing cable, however, would be to swap the dish line now running through the quad grounding block to your spare receiver over to the line running to the tuner 2 input on your HR. The current line from the dish to tuner 2 might be bad. Let's see also how the spare receiver likes that dish line.

    There's always the possibility that one of the four multi-switch ports in the LNB is bad, and that there's nothing at all the matter with your dish lines. That would also make the spare receiver have problems. Since you still have an unused port at the LNB, you could quit using the one connected to tuner 2 of the HR, i.e., the one I'm talking about swapping, and connect to the unused port.

    Also, like Joe, I'm always suspicious of grounding blocks in low voltage DC applications. It could well be that you're not passing the required DC voltages through the block, which can be temporarily bypassed for testing with double-female "barrel" adapters.

    Of course, you could just have a flaky LNB/multi-switch at the dish. evan_S, joe d., eakes, and I: we're all talking about the same stuff here. Lot's of possibilities......:)

    And thanks for your first post. It's a good one!
     
  7. mmanna

    mmanna New Member

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    Sep 19, 2007
    Thank you all for your input - especially letting me know that the lack of a ground on the ground block is nothing to lose sleep over. I probably won't have time to do any additional troubleshooting until this weekend, so I'll check back with you guys when I've had a chance to try some of this. Thanks again! Marc
     
  8. mmanna

    mmanna New Member

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    Sep 19, 2007
    For what it's worth ... I think that I did try reversing the connections on the back of my receiver (moved sat input 1 to sat input 2 and vice-versa), and if I remember correctly, the problems did not appear to follow to tuner 1 as I would expect. I could be wrong, so don't put too much weight or emphasis on this remark. If I am remember this detail correctly, it would normally lead me to say it must be a bad tuner, except for the fact that my receiver has been replaced 3 or 4 times now. Are the LNB's connected in any way inside the dish, or do the three of them operate independently? If so, does it matter which LNB is connected to which receiver(s) input(s)? I see my dish has 3 LNB's ... one which is centered, and two off to one side, with two empty slots where it looks like 2 additional LNB's might potentially go, down the road. Are LNB's something I can get my hands on and replace easily enough, or should I start considering the $80 service call that D* offered me? Marc
     
  9. evan_s

    evan_s Hall Of Fame

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    Mar 3, 2008
    All the lnbs are connected inside the LNB assembly (the head they are mounted on) and have an integrated switch also. There are actually 5 lnbs. The center one has 3 very close together under a single plastic cap. Each LNB receives the signals from a specific location 99,101,103,110 or 119. 99, 101 and 103 are the ones close together under the single center cap. These signals are passed to the integrated switch which then combines them in specific patterns. The receivers then request one of four parts of the total signal and the switch passes that part down the particular cable that requested it. When requesting that signal the receiver also provides power on the cable to power the switch and LNB. It uses either 13v or 18v as both the power and one of the signals for which portion it wants.
     
  10. techrep

    techrep Hall Of Fame

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    Sep 15, 2007
    Here is a pictorial example. This is an AT9 dish but, the LNB layout is the same.
     

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