Some Cable channels suddenly won't come in

[chimneysweep]

Have 3 analog TV's, 1 TV tuner in HP computer, 1- LG 50" HD Plasma with "card" (no converter box). House is 150' from street, cable company had to run new "drop" when I installed the LG Plasma two years ago. Still couldn't get all channels, so cable company installed an AC powered amplifier at the house. Finally, all worked.

Two years later, suddenly several channels won't come in on the LG Plasma at times. When one comes in, the whole group comes in. Or, the whole group goes out (I get a "NO SIGNAL" button on screen). All channels still come in on the analog sets and computer.

Have had the cable techs over four times over this latest problem, and the latest guy replaced the "card" in the LG plasma (didn't change anything), and when this didn't work, said the problem was in the LG HD TV tuner.

1) Is this possible?
2) What would you advise I do next?

[Megahurts]

Have the cable company come with their digital cable box to verify all the channels are receivable at your location.

[Krispy Kritter]

I agree. Until they can prove everything on their side is working, I wouldn't pay to have anyone look at the TV. However, with that being said, since the other TV's are getting the channels, it would appear to be an issue with your TV and not the cable feed.

[TBoneit]

is the LG getting the analog channels and not the HD channels?

I had a problem where the analog channels were fine and the HD channels were out. It turned out to be the drop from the pole to the house was passing analog TV ok but not the higher frequency HD channels and it was also killing the Cable modem service in my case.

As was suggested try using a HD cable box to verify that the signals are really there. It could also be a problem with the amplifier.

[jman98]

chimneysweep - If your cable company is Comcast (this may be true for other companies, but I know from personal experience that Comcast is like this for sure), you need to understand something. Comcast pays rock bottom salaries, even for their industry. About 90% of their employees are clueless morons who will be gone to another low paying job in a few months. Only at most 10% of their work force has what some might call "a clue" or to put it another way, IQs above the, ahem, "mentally challenged" level. The 90% of the employees will look for the easy answer every time. Megahurts is right - they HAVE to come with a cable box to prove that the cable is OK. Is your TV broke? Most likely not.

My best friend and I both have Comcast. My signal is great pretty much all the time. He has constant problems. He has to call them multiple times and get different people to come out before someone with a clue comes to fix his problem. Most of their employees are very very stupid. You need to call and ask for a manager and demand that they send someone out to fix your problem. Demand that they send someone with a digital cable box to test the signal coming into the house. You may have to threaten to cancel everything and go with satellite to get them to come out. Stick to your guns and demand that they help you.

[edDV]

As Megahurts said, test reception of all channels on their cable box first.

If that works and the TV tuner doesn't they may need to work on that amp equalization or amps further up the street.

Back in the 80's when "digital cable" was introduced here, I was one of the first to get it. The upper channels were not equalized well and faded in and out. After several ineffective techs, I demanded an analysis by a senior tech. They had to replace about a mile of cable and add two additional amps in the line to get a flat equalization.

If all else fails, use their cable box and demand free box rent.

[chimneysweep]

Thanks all, for the help & advice. It is ComCast. I called back today and requested an on-site appointment with a supervisor, and asked that he or she have a signal amplifyer and a cable box on the truck, to verify the signal strength as you've suggested. They're going to have a supervisor call me back.

edDV, how can you tell which channels are "upper channels?" Among the ones that pixillate and go out are DISC and the Comedy Channel. Are these upper channels, or does this depend upon the cable company?

[edDV]

Thanks all, for the help & advice. It is ComCast. I called back today and requested an on-site appointment with a supervisor, and asked that he or she have a signal amplifyer and a cable box on the truck, to verify the signal strength as you've suggested. They're going to have a supervisor call me back.

edDV, how can you tell which channels are "upper channels?" Among the ones that pixillate and go out are DISC and the Comedy Channel. Are these upper channels, or does this depend upon the cable company?

On my Comcast system, those are analog channels. Analog channels are usually two digit.
What channel are these there? Here Disc is 63 and comedy is 55 both analog. You should be able to get the analog channels on your other TV sets.

How are the HD channels coming in? Are you getting HBO HD or Disc HD?

What Comcast plan are you on? They should be able to demonstrate all channels available on all plans offered for your address (see Comcast web channel listing for your street address).

If they can't the problem is theirs. If they balk, contact your local gov't cable franchise administrator. His job is to regulate the county-city cable contract. This assumes Comcast isn't financing his boat if you know what I mean.

[chimneysweep]

We don't get HBO, just have basic cable, but DISC is channel 8 here, and COM is channel 60. We have three analog TV's in the house, and they get the signal on those channels all the time: it only pixillates and goes out on the HDTV. In other words, we can be watching a show on the HDTV, lose the signal, and switch to one of the analog sets to continue to watch the same program on the same channel (but not in Hi Def).

[edDV]

We don't get HBO, just have basic cable, but DISC is channel 8 here, and COM is channel 60. We have three analog TV's in the house, and they get the signal on those channels all the time: it only pixillates and goes out on the HDTV. In other words, we can be watching a show on the HDTV, lose the signal, and switch to one of the analog sets to continue to watch the same program on the same channel (but not in Hi Def).

You have a broken TV or the cable/splitter going to it.

What was all this about a "card"? It sounded like you had a CableCard to get the digital channels.

If this was the phone company you would be billed $90 for a problem inside the walls that wasn't their problem.

[chimneysweep]

I must apologize, things electronic baffle me, and I really haven't the foggiest notion how TV signals work.

We do have a CableCard, and get HD channels (just not HBO). On the latest visit, the cable tech replaced the cable card, but that didn't help. I'm sorry I don't know which channels are broadcast in HD. Is it possible the wiring to the HD TV or the TV itself is squelching analog signals? The cable tech looked at our list of the channels that pixillate and go out, and wrote down 669.000 mh in his notes. As I understood him, the channels in question are all on that frequency?

Is it possible that a TV that has worked perfectly for over two years would suddenly lose the ability to tune into a given frequency? Or that the wiring that delivers the signal would suddenly go bad?

[yoda313]

fyi I do have comcast too (michigan) and have noticed that the hd locals sometimes drop in and out through the tv tuner itself.

I have it split three ways with a power amp coax splitter. It goes to my high def dvr, tv tuner and my pc. When I watch the local fox, cbs, and abc etc on high def through the tuner sometimes it blinks out. Not entirely sure why.

I don'tt think I've had any signal problems through the high def dvr so its something funky through the cable itself to the tv tuner. Maybe my splitter isn't as powerful as it could be (though the basic analogs look great).

Just thought I'd offer some more insight.

Good luck though.

[edDV]

I must apologize, things electronic baffle me, and I really haven't the foggiest notion how TV signals work.

We do have a CableCard, and get HD channels (just not HBO). On the latest visit, the cable tech replaced the cable card, but that didn't help. I'm sorry I don't know which channels are broadcast in HD. Is it possible the wiring to the HD TV or the TV itself is squelching analog signals? The cable tech looked at our list of the channels that pixillate and go out, and wrote down 669.000 mh in his notes. As I understood him, the channels in question are all on that frequency?

Is it possible that a TV that has worked perfectly for over two years would suddenly lose the ability to tune into a given frequency? Or that the wiring that delivers the signal would suddenly go bad?

OK, better info. You are on at least a 750MHz system.

Dicscovery on 8 is in the analog VHF band at 181MHz
Comedy on 60 is in the analog cable "hyperband" at 439MHz

It make no sense that these analog channels would be individually dropping without other channels close also having problems. Especially if you are seeing these same channels on other sets. Perhaps your TV tuner has a fine tuning feature and is set wrong.

Analog channels shouldn't be pixelating. If you see pixelation on these channels the problem is in your TV.

Digital channels are a different story. With Comcast the three digit channels are digital. These are usually sent in the upper frequencies ~470-750MHz. 669MHz falls into that band. Problems there will cause pixelation or dropout of three digit channels including the HDTV service. These problems are likely to be in the cable system itself. To separate cable issues from TV issues have them show you that they can tune every channel on their cable box. If they can, the problem is in your TV or the way they programmed the CableCard.

[chimneysweep]

I went through the tuner, and here are the stations that go out:

8-DISC
38-Learning Channel
58-USA
60-Comedy Central
61-County Music Television
63-MTV
67-AMC

The past two days, these channels, which "came and went" on the HD TV for the past month, have not come back on at all (at least not when we tuned in and looked). All come on just fine on the other (analog) sets in the house.

Do these channels have something in common that might be a clue to the problem? Or does this indicate that something has gone wrong with the tuner in my HD set?

[Megahurts]

You said your'e using a cable card which is used with digatal cable. The bad chan list suggests your using analog cable.

Your Plasma TV has 2 tuners, a Qam tuner (digital cable tuner which uses a cable card) and an analog broadcast/cable tuner. Which tuner is the cable plugged into?

If it's using the analog tuner then chan 8 uses 'VHF-Hi band' which includes chans 7 thru 13. If these channels except 8 are fine, then your tuner is OK. The other channels mentioned are on the 'Super and Hyper bands' which the same applies. A simple test would be to hook up another tv to your Plasma cable outlet.

Also, do all the bad channels go out at the same time?

[chimneysweep]

All seven affected channels go out at the same time. In fact, at this point they never come in at all. My LG plasma just has two co-ax connectors: one is labeled antenna, and the other (the one we're using) is labled cable. This cable supplies the signal for both the analog and digital channels.

Our Comcast subscription only includes a half-dozen HD channels, and all come in just fine. It is seven of the analog channels that don't come in.

Update: this weekend, I pulled the CableCard out of the TV. With the card removed, the seven channels come in, but the HD channels don't.

I've made an appointment to have a ComCast supervisor bring one of their set-top tuners over this week to see if the "magnificent seven" come in through the box. If they do, am I right to suspect either the TV tuner or CableCard has gone bad?

[edDV]

All seven affected channels go out at the same time. In fact, at this point they never come in at all. My LG plasma just has two co-ax connectors: one is labeled antenna, and the other (the one we're using) is labled cable. This cable supplies the signal for both the analog and digital channels.

Our Comcast subscription only includes a half-dozen HD channels, and all come in just fine. It is seven of the analog channels that don't come in.

Update: this weekend, I pulled the CableCard out of the TV. With the card removed, the seven channels come in, but the HD channels don't.

I've made an appointment to have a ComCast supervisor bring one of their set-top tuners over this week to see if the "magnificent seven" come in through the box. If they do, am I right to suspect either the TV tuner or CableCard has gone bad?

You should also call LG support and explain the analog channels coming back when you pull the CableCard. They probably have heard this one before.

When you pull the cable card you should be losing all the digital channels (above 99).

[chimneysweep]

edDV, I thank you for your help here. You and the other posters have been an invaluable resource in tracking this problem down.

I called LG support last week, and, having first determined that I'm out of warranty, they had no opinions to offer as to what might be causing this problem. They did give me the number of a local authorized LG repair company, who says they need to perform a service call before they can offer any advice. I don't want to pay for that until I've ruled out any ComCast problems, so at this point, I'm waiting for their next visit.

[edDV]

edDV, I thank you for your help here. You and the other posters have been an invaluable resource in tracking this problem down.

I called LG support last week, and, having first determined that I'm out of warranty, they had no opinions to offer as to what might be causing this problem. They did give me the number of a local authorized LG repair company, who says they need to perform a service call before they can offer any advice. I don't want to pay for that until I've ruled out any ComCast problems, so at this point, I'm waiting for their next visit.

You always have the option to use the cable box instead. That will save an expensive repair.

[chimneysweep]

Finally had a fifth visit from Comcast yesterday. The tech brought a set-top box and hooked it up to the cable. All channels came in through his box, but there were bands of electrical interference flickering on every channel. He couldn't figure out where this electrical "noise" might be coming from. Eventually, he unhooked his box, unplugged the TV, pulled the cable card and re-inserted it and reconnected the cable directly to the TV like it had been.

Voila. When he plugged the set back in, all stations, including the "problem 7" on band 669.000 came in clear as can be. As of this morning, all is still well.

The tech had no idea what he did that solved this problem. Just guessing, he opined that the cable card or TV itself had somehow developed an electrical charge over time, and that unplugging both the card and the set removed the charge? The TV goes into "sleep" mode when we turn it off, and when he unplugged it, that was the first time since we bought it two years ago that the current was interrupted and the set was actually off.

At any rate, we're back up and running, and I want to again thank everyone on this forum for the help.

[SingSing]

Look like you are receiving analog signal with your TV.

Switch the cable to the antenna side, and see whether that help.

Most TV has dual TV tuners for "Picture in Picture", so if one of them has issue, then just switch to the other port.

[edDV]

If there is interference on the line that enters the house, it is the cable company's responsibility to fix it. If the interference comes from within the house, it is your responsibility.

Most TV sets today don't fully turn off when swiched off. Even if you have a power outage, there is an internal battery or capacitor that keeps the settings memory active for a short period (similar to CMOS settings on a computer).

What you did was a hard reset to restore original factory defaults. That should be the first thing you do when an electronic device develops quirky behavior even after turning off and on again. Some devices need to be left unplugged for several hours to empty the settings memory. Then when plugged in, they will return to factory default configuration.