No Signal Strength On Odd Transponders for Sat A(101)

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CMOS

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Jun 18, 2008
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Sometime yesterday afternoon I noticed my SAT searching for a signal on a channel that I normally get. I figured there must be some cloud cover and went about my daily business. When I got back last night and checked it again, I still wasn't getting that channel and there was no cloud cover. I did a signal check and noticed that all my odd transponders on SAT A(101) are all 0 but my even transponders are in the 90s to 100. SAT B and C transponders all get their normal signals as well. This issue is affecting all 5 receivers in my home(2 HD receivers and 3 DTivo).

I checked all the cabling to ensure that everything was connected firmly, wasn't wet and had no corrosion; found no problems. I replaced my multiswitch with another multiswitch and the problem remains.

I called DirecTV to schedule a service visit but A.) The guy won't be here until Thurdsday and B.) They want to charge me some 60 dollars so I would like to resolve this issue myself if possible.

I believe it might be a failing LNB. Is there any way I can confirm this hypothesis or does some kind soul(s) here have other suggestions?

Thanks.
 
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VewDew

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Feb 4, 2004
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I had this exact same problem about 2 weeks ago and it was the LNB in my case. Once they replaced my LNB everything was back.
 
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hugromieo

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Feb 11, 2007
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locate the 13v 101 line coming into the multi switch and test the signal on that line, if there is no signal check that port at the lnb. my guess is the lnb is bad, but it could be the cable or connector...good luck
 
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philhu

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Sep 1, 2004
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I have expressvu, and older lnb's...Same symptom, ended up being the LNB

Replaced it with an old Directv lnb, worked fine.
 
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Joe Diamond

SatelliteGuys Pro
May 3, 2004
2,596
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The fact that this is on all 5 receivers is a clue.
The problem is in the multiswitch, the cable & fittings between the LNB and the multiswitch or the LNM itself. Try tapping the LNB with a wrench...fix?....Then.....Switch the leads (at the multiswitch--easiest) and see if the problem moves to the 18v.

Probabaly dead multiswitch.

Joe
 
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CMOS

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Jun 18, 2008
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I've replaced the multiswitch to no avail.

As far as testing the 13V line... how would I go about that? I have a DMM but I assume I'm doing something wrong as I am getting a zero for all 4 lines tested. I just assumed it was as easy as placing the positive and negative leads against the conductor but as stated this returned zeros for all 4 incoming cables. I tried it on a setting of V DC and V AC.

Thanks for the help so far... appreciate it.

EDIT:

I also switched the 13V 101 cable with the 18V 101 cable going into the multiswitch. This resulted in gaining all EVEN transponders but losing all odd transponders. So the situation reversed itself.
 
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texasbrit

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Then you need a new LNB.

No, in fact exactly the opposite. If you swap the two cables from the multiswitch to the dish and the problem moves from odd to even transponders that almost always indicates the problem is in the cable.
 
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CMOS

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No, in fact exactly the opposite. If you swap the two cables from the multiswitch to the dish and the problem moves from odd to even transponders that almost always indicates the problem is in the cable.

Okay... so in order to test the cable I assume I need another cable to run, right? The cable goes quite some distance though, not sure if I have enough lying around.

Is there a way to test the cable? I assume this involves the DMM mentioned earlier but I'm still not sure how to test it.

Thanks guys.
 
jcrandall

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No, in fact exactly the opposite. If you swap the two cables from the multiswitch to the dish and the problem moves from odd to even transponders that almost always indicates the problem is in the cable.

THink you're right tex - didn't think that one through enough before replying... :(

Check the cable for any damage (dog bites, cuts, etc). If it looks good everywhere, try replacing the connectors (and recutting the wire at the tip - cut off and start over on the end) before running a new wire.
 
iwc5893

iwc5893

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Feb 1, 2007
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Okay... so in order to test the cable I assume I need another cable to run, right? The cable goes quite some distance though, not sure if I have enough lying around.

Is there a way to test the cable? I assume this involves the DMM mentioned earlier but I'm still not sure how to test it.

Thanks guys.

To test the cable, you need to disconnect it from both ends (at the dish and the switch). Use a multimeter with the positive on the conductor and the negative on the connector. Measure resistance (ohms). It should indicate an open circuit (1.000). If it indicates anything else, then there is a short in the cable somewhere.

To test the switch, swap the 13VDC cable and the 18VDC cables on the input to the multiswitch. Check your signal strengths. If the problem moves to the even transponders, it is a cabling/connection issue (or a bad port on the LNB). If it stays on the odd transponders, it is an issue with the multiswitch or the LNB.
 
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texasbrit

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Okay... so in order to test the cable I assume I need another cable to run, right? The cable goes quite some distance though, not sure if I have enough lying around.

Is there a way to test the cable? I assume this involves the DMM mentioned earlier but I'm still not sure how to test it.

Thanks guys.

So far your testing shows it's not the multiswitch, it's the cable or (rarely) a port on the LNB. iwc5893 posted a reasonable way to check out the cable for most problems. Another thing you can do while you are at the dish is to swap over the "faulty" cable to a different port on the LNB. If the problem stays with the cable, then you definitely have a cable/connector problem. If the problem moves, that would indicate a bad single port on the LNB, but that is quite rare, cable problems are much more common.
 
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CMOS

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Jun 18, 2008
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Thanks for the help guys...

I wasn't able to take care of the issue prior to the technician arriving so I guess I'll end up eating that charge.

He replaced my multiswitch to confirm my finding that the multiswitch was not the issue. He looked at the dish and replaced an LNB. All transponders returned without issue. We also took that chance to inspect some connections and noticed there were 2 connectors that had corroded conductors that were very close to falling off.

All in all a happy ending.

Again, thanks for the help... I learned a lot that if necessary I can probably save myself a future service call. :up
 
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rlongwell

Well-Known SatelliteGuys Member
Sep 1, 2007
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I believe I'm presently experiencing the same thing - I happened to read this post and swapped the incoming 13V and 18V lines, and the odd numbered transponders from Sat 101 which were showing zero CONTINUED to show zero (didn't swap over). This indicates either the Zinwell multi-switch OR the LNB. But Direct TV is coming tomorrow, so they'll verify. It's probably just as well, my setup is less than 6 months old and covered. Plus I don't happen to have a spare LNB available :)
 
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