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Discussion Starter · #1 ·
In our bedroom we have a Motorola DCT-2500 hooked up to a Toshiba LCD via composite patch cables. Recently it has been having issues with the screen going black for 1-2 seconds, but only on certain channels. The audio is fine.


For Eastlink Cable it is channels 185-189 (worse on 186 and 187). It happens every few minutes or so. We have two other boxes in the house with no issues at all. All feeds are split from one master source.


Here is what I've tried so far, none of which made any difference:


* Swapped out all cables (everything from the patch cables to the coax, as well as trying s-video)


* Tried alternate inputs on TV


* Brought up another DCT-2500 cable box, same results


* Attached a 10dB powered signal amplifier


If I move the TV downstairs and hook it up to our DCT-6412 DVR cable box (also using composite), it works perfectly. It only seems to be the bedroom feed, which was fine for the 6-7 years or so we've lived here.


I'm thinking that if it was the TV, all channels would have problems as it would be related to the video inputs, and it wouldn't work using the other feed.


I don't think it's the box as the other box also had the same problem when accessing the same feed. Could this be a signal issue? How could it localize to a specific channel range?


Thanks.
 

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It's probably the cable/coax run to that particular location. Swap the cable feeds at the master source (splitter I presume?) and see if the trouble/symptoms move.
 

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The only thing you didn't mention was to take the box to another location!

Are there any more splits along the way from the first one to the TV in question?
 

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Quote:
Originally Posted by RCbridge /forum/post/18300550


The only thing you didn't mention was to take the box to another location!

Isn't this essentially the same test?

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* Brought up another DCT-2500 cable box, same results
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by Ratman /forum/post/18300391


It's probably the cable/coax run to that particular location. Swap the cable feeds at the master source (splitter I presume?) and see if the trouble/symptoms move.

Ah, easier said than done. It's all in-wall, from the basement to the upstairs bedroom. I'd like to make 100% sure it is the feed before I undertake that mission...


Quote:
Originally Posted by RCbridge /forum/post/18300550


Are there any more splits along the way from the first one to the TV in question?

Nope, it goes direct from the wall into the back of the cable box.


I just took a look at where the master feed comes in. The cable coming into the house seems to have a 2-way splitter sending one patch to a 3-way splitter (which must feed our downstairs office, rec room, and perhaps another bedroom) while the other goes upstairs into the ceiling. Our bedroom is directly above this panel, so I wonder if this is a direct feed? I'll have to try a few things and see where all this spaghetti is going.


Thanks for the replies...
 

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You have a two-spliiter at the entry of the coax (master feed).

One output to a three-way, the other direct to the the bedroom (problematic) TV.


Assuming that's correct, you have more loss to the devices attached to the 3-way that don't have a problem. So... signal power shouldn't be an issue. Nor the drops after the 3-way splitter.


Simple test. Swap the coax on the output ports from the 2-way splitter. Of the other devices show the problem and the bedroom TV is "fixed", you probably have a bad 2-way splitter.



If the problem doesn't change, then you have to look at the coax run to that particular TV. It could be a bad connector, wall plate, etc... Should be fairly simple to isolate since it's only one drop after a 2-way splitter. (Unless... you have rodents chewing on your coax cables. Then you have two problems to resolve.
)
 

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Quote:
Originally Posted by SithLord /forum/post/18301127


The cable coming into the house seems to have a 2-way splitter sending one patch to a 3-way splitter ...

Not all splitters are created equal. This post describes and pictures standard splitters, some obsolete and some current:

http://www.avsforum.com/avs-vb/showt...0#post18161330
 

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If the existing splitters were "obsolete", why would it affect only one TV while the others work fine?
 

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Discussion Starter · #10 ·
Sorry for an old bump...got sidetracked with personal issues and had no time to investigate this further. The problem still continues. Tonight I made a few discoveries:


Used the diagnostics screen to view the frequency details for the channels that blackout (186, 187, 188 and 140, probably others but don't watch enough to notice). The trouble channels all fall within the 500 range. Channel 185 is on freq 465 and does not blackout, so it seems only channels on certain freqs are having issues.


I repeated a few of my earlier experiments. Replaced the Toshiba LCD with a CRT, got blackouts. Took the LCD downstairs and attached to the DVR (DCT-6416), no blackouts. Took both the DCT-2500 cable box and LCD to the downstairs feed, got blackouts.


So, it seems the trouble is related to both the channel frequency and the way the signal from the DCT-2500 is either sent or rec'd by the TV.


Does this make any sense? Does anyone know how to further troubleshoot this?
 

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Quote:
Took the LCD downstairs and attached to the DVR (DCT-6416), no blackouts. Took both the DCT-2500 cable box and LCD to the downstairs feed, got blackouts.

This alone points to the STB, the last thing I would do is move the DCT-6416 to that other location if it works fine you can eliminate the location as the issue and really look at the DCT-2500.
 
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