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"No signal" on HDTV from cable box.

by jimalcorn / March 28, 2010 5:22 AM PDT

My Samsung HDTV displays "No signal" for the cable box. If I unplug the HDMI cable, it says "Check signal cable." This makes me think that the tv recognizes the cable box.

Comcast says it is a problem with the TV. Samsung says it is a problem with the cable box. If I hook the cable box up to another tv (which is a pain) it works.

The cable box worked great for months then it quit working (it was less than 6 months old). I replaced the box at Comcast and it didn't change. I replaced the cheap, Comcast HDMI cable with the one I used for the BluRay and it worked but the cheap HDMI cable didn't work on the BluRay. So I bought another HDMI cable (same model) for the cable box. It doesn't work on the cable box. The BluRay works on all of the HDMI inputs on the tv - so there is no problem with the inputs.

Samsung LM52B750U1FXZA
Scientific Atlanta cable box: 4250HDC.
RocketFish cables: RF-G1160

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"No signal" on HDTV from cable box.
by Samsung_HD_Tech Samsung staff / March 30, 2010 2:32 PM PDT


I'm sorry to hear that you're having this problem.

Try changing the video output resolution in the cable box with a TV that works. Often times, a No Signal issue can occur when the resolution isn't one that the television recognizes.

Another issue is that the HDCP chip in the cable box may be bad, which might explain why it might work on one TV and not another. If the cable box continues to give you an issue, you might want to have a service tech from the cable company come out and check your lines. If it still doesn't work, then the television may need to be inspected, and that can be done by calling 800-SAMSUNG.

Keep me posted.


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no signal problem
by murph8447 / September 8, 2011 11:57 PM PDT

We had the same problem after I changed the resoultion from 1081i to 720i by accident. The cable company could not help us. So I read this thread. My husband decided to uplug everything and leave it off for a while when he turned everything back on it worked! Don't know why but he seems to think the tv reset it self. try this if you have his problem

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"No Signal" on Smart TV from cable box
by carawithacee / November 17, 2014 11:36 PM PST

I had this SAME thing happen! Including, 2 replacement cable boxes (that worked briefly - just long enough for the cable guy to leave) and multiple calls to Comcast/xfinity.

I tested everything,as the above and finally today - the electricity in my apartment was shut down for about 20 mins. and when it powered back on it worked! I live in a brand new apt complex only 1 tenant prior to me and they had Direct TV - so I'm not sure exactly what happened but once everything was shut off including the cable outlet - it seems to have reset itself and is now working. It's only been about 20 minutes but this was so frustrating that I had to post so no one has to go through this....

I think it's combination of Samsung/Comcast/xfinity technologies trying to control the platform.

So hopefully this helps someone get this fixed!

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