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carmine

join:2002-09-30
Waterbury, CT

3 second blackouts

Yesterday morning I disconnected all of my U-Verse equipment and had Comcast Digital Preferred TV + Performance Internet installed. Let me say first that I instantly noticed the greatly improved picture quality on my HD TV; I had read this before but always thought the U-Verse picture was fine until I could compare them for myself.

I am also extremely happy with the Internet spped which is testing out at more than 25mbps down and nearly 4mbps up - better than double what I was getting with U-Verse "Max" at $48/month.

So, anyway, while watching HD channels last evening, the TV screen went totally black and I lost audio for 2 to 3 seconds, then everything returned to normal. This happened a total of four times over a period of a few hours.

Since it never happened before, I am inclined to believe it is not a problem with the TV itself.

Any thoughts on the cause? Should I request a service call? FWIW, I have what I understand is the "new" Cisco DVR stb.

As an aside, what I do miss about U-Verse is the Picture-in-Picture browsing which lets you easily see what else is on tv at the moment or later without having to access the Guide screen. »www.att.com/u-verse/explore/feat···_xVMVfXI


bmurm

join:2002-05-14
Pittston, PA

I had the same problem it was the box. I thought it was my tv too. Changed the box and has not happened yet.



trythisfirst

@comcast.net
reply to carmine

While it could be the box, it could be the power cord as well if it has one of those bricks attached to it. It could also be a cheap or worn out surge protector. I would just keep this in mind, but i wokuld get a new box.


carmine

join:2002-09-30
Waterbury, CT

I don't think it is power-related (cord, power strip, etc) because the stb doesn't go totally dead; if it did, it would take a lot longer than a few seconds for the picture and audio to return, wouldn't it?

I can probably test this theory by pulling the plug for a few seconds but don't think it is necessary.



flwpwr

@comcast.net

This is correct, it would take minutes to reboot if it lost power, and your guide would be "to be announced".

It is one of two things, bad box, or possible bad HDMI cord if he has one connecting the HD to the TV. Well it could be a real weird cable issue, but usually its the box or HDMI cable if its happening while watching and not changing channels, its normal to black out when switching between SD and HD or HD and SD channels for a few secs but that's only when changing the channel and not when just watching..



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
Reviews:
·Comcast
reply to carmine

First of all welcome to Comcast.

I wouldn't worry about this issue if it has only happened once. If it was a constantly recurring problem where watching programming was impossible then it would be a more serious problem. If this issue occurs while watching recordings from the DVR then it could be an issue with the DVR. Most likely this issue is just a glitch in the feed coming in from the content provider.

Now this is something I've noticed with my own Cisco RNG200N and a Toshiba HDTV connected with an HDMI cable is that when I tune to certain HD channels both the picture and video blank out for a second every time, but when I connect the same box to the same tv with component cables that issue doesn't occur. I've already replaced the box and the same issue occurs but only when using HDMI and tuning to certain HD channels.


carmine

join:2002-09-30
Waterbury, CT

It happened four times last night (the first time watching TV since install earlier in the day). Each event lasted just a few seconds and then recovery was instant and complete. It happened while simply viewing an HD channel; not while changing channels or anything like that.

I am connected via an HDMI cable, supplied by Comcast. I still have the one that was previously used with the U-Verse box; maybe I will swap them and see if anything changes.



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
Reviews:
·Comcast

I don't think its an issue with the HDMI cable being bad, could be the feed Comcast is recieving or it could be an issue with the HDCP handshake between the tv and the box (which can't really be fixed just avoided with use of component cables) I have a few component cable bundles supplied by Comcast I don't need if your interested for free.


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to carmine

Did it occur during the middle of something, or during a commercial change.

Sometimes, when Comcast inserts commercials, they don't always upconvert to HD, so it switches to SD for the commercial, then back to HD for the network feed. Depending on the TV, the picture/audio may go out for a few seconds.


carmine

join:2002-09-30
Waterbury, CT

@Mike Wolf: Thanks for the offer; I have two or three sets of good quality component cables already. I'll will give them a try as well.

@andyross: I will have to pay closer attention; as I recall it always - or at least some of the times - happened in the middle of a broadcast and not during a commercial break. Can't be certain though...


ak3883

join:2005-08-20
Portsmouth, RI
reply to carmine

My money is on HDMI. I'm no longer on Comcast, but for the last several months up until I left in July, my DCX3400 box would sometimes go blank for a second or two(however my audio wasn't interrupted). Sometimes I would get a green flash too, which indicates HDMI. It was not annoying enough to switch to component cables, I hardly even noticed it after awhile really. This happened completely at random, maybe once or twice an hour. I think it is/was related to the current version of firmware that was on the box, and it's HDMI implemenation, rather than a faulty HDMI cable or port, like Mike Wolf suggested.

Try component and see if that fixes it.


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to carmine

I have an old DCT-6412P2, which has DVI. The TV is a recent Sony and I use a DVI-HDMI cable direct to the TV. Audio goes to my receiver via optical.

I haven't had any real blackout issues, other than when changing resolution. I do have it configured to send SD as SD and not to upconvert.

The only issue I occasionally have is that it suddenly will not display SD material if I switch to it from HD, or even another source. Seems as if SD and HD may have separate handshake encryption codes or something like that. Typically, turning the TV off and back on fixes it. It may be a TV issue rather than the box. I tried using component for awhile (my old TV had DVI, but it didn't work well), but in SD, the new TV has a high black level compared to HD, and I can't set it without screwing up HD as it's set by input, not resolution.


carmine

join:2002-09-30
Waterbury, CT
reply to carmine

FWIW, the problem persists even after switching from HDMI output to component video/audio (5 wire). Also after ComcastSteve performed a "signal hit" (what is that anyway?) followed by rebooting the RNG200N at my end.

Don't know if it is meaningful, but my SB6121 cable modem's log does not show any incidents such as dropped signal which would coincide with the TV dropping out (in fact, the modem's log is clean except for the initial power up sequence).

I suppose that indicates that the wire from pole-to-house is good. The ground block/splitter has 4-outputs with one wire going to the basement where a two-out splitter feeds the SB6121 modem as well as an Arris TM604G/CT telephony modem (for a business class voice line which is on an entirely separate account - long story).

The other three outputs on the main splitter feed three potential TV's, only two of which are actually installed. One has the RNG200N DVR and the other a simple digital adapter. I will say that the wire going from the splitter to the RNG200N is at least 8 years old and possibly quite a bit more.



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
Reviews:
·Comcast

hmmm i personally don't like that ground block setup. I generally try to keep it simple.

wire from the pole goes through the ground block on a 1:1 scale. that cable goes into the house and connects to a splitter, from the splitter it goes to the rest of the house. This way its easier to know whats going on.

That cable that is coming off your ground block and goes directly into the RNG200N could be going bad. If that's so there would not be any evidence on any of the other devices because everything else is being fed off other outputs. A way of checking for this is either replacing that cable, or swapping the devices connected to the cables, ie put the modem on the cable the RNG is on and put the RNG on the cable the modem is on. If you see issues with the modem or if the blacking out issue goes away then we know its a bad cable. If the issue follows, then it might be a bad ground block splitter peg. You could simply go to the ground block and swap the cables from there, so like if the RNG was on peg 1, a tv goes to peg 2, a tv goes to peg 3 and the cable modem/voice modem goes to peg 4, you would put the cable connected to peg one on peg 3 and the cable that was previously on peg 3 on peg 1. I know it sounds confusing and its difficult to explain it in words. Man I really wanna resolve this issue for you


carmine

join:2002-09-30
Waterbury, CT

Maybe these screenshots will help (TV on, STB off, push Select & Info simultaneously, then scroll through screens).

carmine

join:2002-09-30
Waterbury, CT

I don'tknow if a direct comparison can be made, but signal levels at the SB6121 are very good:

Downstream  Bonding Channel Value 
Channel ID 205   206   207   208   
Frequency 699000000 Hz  705000000 Hz  711000000 Hz  717000000 Hz  
Signal to Noise Ratio 36 dB  36 dB  36 dB  36 dB  
Downstream Modulation QAM256  QAM256  QAM256  QAM256  
Power LevelThe Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading  
 -6 dBmV   -6 dBmV   -7 dBmV   -8 dBmV   
 

Upstream  Bonding Channel Value 
Channel ID 3   
Frequency 30000000 Hz  
Ranging Service ID 85  
Symbol Rate 5.120 Msym/sec  
Power Level 48 dBmV  
Upstream Modulation [3] QPSK
[3] 64QAM
  
Ranging Status  Success  
 

The groundblock/splitter is new, by the way - an Evolution EV01-SP-4 with -7db drop on each of the four outputs. As already noted, the wire going to the SB6121/Arris telephony modem is split again - an Extreme BDS102H with -3.5db drop on each out.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
Reviews:
·Comcast

1 edit
reply to carmine

The software anomalies page doesn't help much because my boxes show the same things and I'm not having signal problems.

ok current qam status and second qam status being unlocked isnt good, and I think its because the signal level is -20 dBmV. Generally it should be in the signal digits on either side of 0. Mine for example is -5 dBmV for both and locked. I'm not a big fan of the signal noise either.

have you tried putting the box on another line or tv and seeing if the issue occurs? could be a bad coax wire going into the box. Or it could be the tuners in the box are aging out.


carmine

join:2002-09-30
Waterbury, CT

said by Mike Wolf:

have you tried putting the box on another line or tv and seeing if the issue occurs? could be a bad coax wire going into the box. Or it could be the tuners in the box are aging out.

I can give it a shot, but not sure how valid a test it might be.

The best other wire I can try it on is only about 8 feet long from the ground block/splitter and is brand new. However, the TV in that room is an aging SD set and it would not be practical for me to drag the big HD set along for the test. Nevertheless, I should at least be able to see if the signal levels improve on the short, new, wire.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

ok let me know. if the issue doesn't resolve itself before December 25th I can still pop in and see what I can do if you want.


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to carmine

When you used the component output, did you DISCONNECT the HDMI cable? Leaving it connected can still leave it active and cause re-handshaking issues.


carmine

join:2002-09-30
Waterbury, CT

said by andyross:

When you used the component output, did you DISCONNECT the HDMI cable? Leaving it connected can still leave it active and cause re-handshaking issues.

Yes, I sure did.

carmine

join:2002-09-30
Waterbury, CT
reply to Mike Wolf

Click for full size
Click for full size
Okay, so I moved the DVR down to the other room where it is connected to about 8 feet of new wire coming directly off the new groundblock/splitter.

After giving it about ten minutes to settle down, you can see from the images above that the levels are much, much, better. I don't have time just now to sit there for the next hour and wait to see if it is going to black out again; that may have to wait until tomorrow.

Also, in response to an earlier question, the status screen indicates that my RNG200N has a 465GB hard drive.


joe0307
Z3

join:2001-06-25
FL/NY
reply to carmine

You wouldn't happen to have a Sony, would you?
»forum.sel.sony.com/viewtopic.php···&t=10540


carmine

join:2002-09-30
Waterbury, CT

said by joe0307:

You wouldn't happen to have a Sony, would you?
»forum.sel.sony.com/viewtopic.php···&t=10540

No, it is the Cisco RNG200N.

And, it turns out that the signal levels are not stable no matter which location in my home I hook it up to. Sometimes it shows Status: Locked, Level: -5db, S/N: 36db. A few minutes later it is back to Status: Unlocked, Level: -20db, S/N: 0db.

I am guessing it is a bad box and ComcastSteve seems to agree. I went to the office an hour ago (it is just 1-1/2 miles away) with hopes of exchanging it, but there was a line of at least 10 people and I didn't feel like waiting.

Maybe tomorrow morning...


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

aww sorry to hear about the box and line, hope that solves the problem. if not let us know please.


kable

join:2011-11-21
Brewster, NY
reply to carmine

Hello Carmine,

I have experienced the same problems. I have already replaced (exchanged) my TV and also audio/video receiver. Also, I have changed all of the HDMI cables. While watching live or recorded programs from the Comcast DVR (anywhere) cable box, the screen goes totally black for 3-5 seconds. It happens randomly and can be twice or five times in one hour. The picture always comes back and we never lose the sound. This never happens on a DVD. I am ready to contact Comcast and request a new cable box. This problem has been occurring for about the last two months.


stanely

join:2003-01-04
Hopkins, MN

Your HDMI cables are fine. Replacing the box will not fix the problem. ALL Anyroom RNG200N using HDMI will be affected by this bug. The recent R27 software update does not fix this issue.

It's either a HDCP handshake issue or a bug with CEC implementation.

If the timeline for fixing previous problems is any indication, don't expect a fix until next summer. Don't you just love this new software guide? It's Comcastic!



Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3
Reviews:
·Comcast

we already went over the issue with the hdcp handshake blankout, and after i tried component cables the issue went away. the OP did the same thing but the issue continues to occur apparently. OP wants to change out the box to correct the issue of the box not being able to lock onto the signal.


carmine

join:2002-09-30
Waterbury, CT

said by Mike Wolf:

we already went over the issue with the hdcp handshake blankout, and after i tried component cables the issue went away. the OP did the same thing but the issue continues to occur apparently. OP wants to change out the box to correct the issue of the box not being able to lock onto the signal.

True; switching from HDMI output to component video and audio cables (the five-wire variety) did not solve the problem. And, the other poster's comment is on target: it may happen once every 20 minutes or three times in a span of five minutes.

Always the same; the screen goes black and audio is lost. The event lasts for two to three seconds and then everything returns to normal as if nothing had happened.

I will swap out the box and see if there is an improvement.


Mike Wolf

join:2009-05-24
Beachwood, NJ
kudos:3

yeah that sounds like a loss of signal which is shown by what we discovered yesterday in the diagnostic screens. good luck.