Some HDTV's locking up

It has come to my attention that there are some HDTV's with a peculiar problem.

And that is locking up on off air digital TV channel 25, (25.1, 25.2) what happens is the TV's will quit responding to any commands from the remote control or from panel controls, the only way to resolve this is to unplug the off air antenna and unplugging the AC power for 30 seconds, this clears the problem until you watch channel 25 for a bit.

The sets affected by this problem are the Sharp Aquos, and some Sony's, this is being reported from the Denver and Lakewood areas of Colorado, this has been reported on other sites as well.


Anyone with this type of problem in other areas of the country please post you experience here, and any solution you or the manufacture found.


Your help with this will be greatly appreciated by all afflicted by this problem.

Terryl

After reading your post, it did trigger a problem that I have been having in the last two weeks. I have 3 HDTV's: Sony-52, Vizio-37, RCA-24 with the first two being 1080P.

After I read your post, I revisited my TVs and found that the Vizio and RCA were okay however when I checked my Sony supply guide (actually TV-Guide), I found problems.

I reset the guide (overnight fill via guide ) but the TV rebooted on its own. After it rebooted, I requested the same, and again it rebooted. Finally after 3rd reboot I was able to access the guide but the info remained. I had to manually remove old data. Will report back later to see if problem solved.

Finally after 3rd reboot it seem to work

Sanyo 32 inch does this on any anolog channel. Whe you scan channels it always finds an analog channel even when there is no station on channel (can't delete channel either)
If you scan through channel and don't let channel come in snow it locks up have to unplug and plug back up then hold power button dow on tv until it shuts off to unlock it.
I have 2 of these purchased in North Alabama

I do not have channels 25.1 or 25.2 here in northeast, USA. Are they locals or network stations?

Btw I checked my guide today and it was set to broadcast data update, which no channels showed no info so I switched back to TV-Guide updates (which is actually updated at midnight via my wireless connection and not via cable connection-SEE * in quote).

I did go back and checked which channels where having problems and they were all QAM256 SD. The analog and the HD for these channels came in good. The only info on the tuner I could find was this:

Quote:

---

NTSC: American TV standard
ATSC (8VSB terrestrial): ATSC compliant 8VSB
QAM on cable: ANSI/SCTE 07 2000 (Does not include CableCARD functionality)
*Download Acquisition Mode (DAM) is used for software updates and/or collecting data for TV Guide On Screen.

---

I wonder if this could have something to do with the way those particular TV's are handling ancillary data (guide, etc...)? Could also be a problem on the station's end, maybe there's an issue with a certain brand of MPEG encoder...

I now have two sets of guides (i.e.-channels), one listed after the other. I also have a lot of double channels per each guide.

I am beginning to believe that there was an major DAM Tv-Guide update a couple of weeks ago and maybe has affected a particular tuner/interface/etc.

I am going to reset my guide again and change providers as I had two listed for update choices, both being Comcast.

Problem similar to this on three converter boxes--Channel Master D2A, Digital Stream, and RCA DTA800B1. Problem seems to happen when there is a combination of weak signal with heavy multi-path or with skip caused by Sporatic_E or frontal passage.

As the only common code between these boxes is the proprietary code for digital TV format and AC3, and AC3 has been around a long time, I'm thinking that there is a bug in the DTV format code. Maybe some test code that was left in and the corruption of data under the extreme conditions just happens to get the code into it, or maybe something the coders should have taken out but did not, or something the gov made them put in. Could be something to do with guide data too, hard to really say, or the switching between distant and local channel data in stream under the conditions--lots of possible faults, little data.

The processors in the boxes are STMicro (with separate processor and decoder chips) in the Channel master, Broadcom in the RCA and LG in the Digitalstream

I am connected straight to my TV jvvh5897 so no cable box is needed. Checking my guide today I noticed that only one of my double channels/per guide had info so there was a guide update last night.

I am in process of deleting all the "static" channels but since there are ~ 250 of them, if may take a while.

Interesting though is that I haven't been able to find info, other then general stuff, concerning the DAMs update and since it is via wireless and not via cable (therefore not Comcast) it must be contracted. I guess I'll log my router and see where is it is from.

For those that might be interested in testing the problem, I do have a jtag dump from the Channel Master box. There is also un-documented serial port on the RCA box--there is a 5 pin connector near the back panel that has TTL level serial RX and TX with the other pins as ground and with the serial port you can get into a menu that allows a read of the current channels info including PIDs--my best guess is that under Sporatic-E you get a distant channel as strong as you get the local channel, so that PID info should change. In my tests the RCA did the best at recovery under bad conditions, but it too at times locked-up. The RCA DTA800B1 did not have the same tuner as the Broadcom based DTA800 and did not seem as good with week signals, but handled the dropouts with blanking the screen rather than leaving aritfacts.

One could also test the signal with usb TV tuner and linux--they have a "scan" feature that tests the PIDs. Or one could do a "spectrum analyser" with a TV tuner module like you can see over at the mtmscientific site.

As I understand it all digital systems whether converter box or TV use similar chips inside--there are only about 4 chip makers that are licenced to use the propritary TV code.

I live in Arvada Colorado a suburb of Denver and have a Sharp Aquous. This happened to me starting several weeks ago. I know very little about the technical details of digital TV so this is what I went through.

Initially I thought something in the TV went bad, I was unable to do anything even after unplugging the TV for 15 minutes. It always came back on to channel 25.1 and I was unable to use either the remote or TV controls to change anything. So I looked through the manual for a reset button or something and found nothing. then I found the cold reset procedure for the Aquous on the internet and completed the procedure. My TV was back working just like it was new out of the box.

Thinking that it was maybe a one time happening after I got everything setup I went back to channel 25.1 and it locked again. I reset again and this time I locked out Channel 25.1. Everthing works fine as long as I don't go to 25.1. Not a problem since this is a Spanish channel. However, my wife speaks Spanish and sometimes likes to watch the Spanish channels. OK, I have a 37" Vizio also that that did not exhibit the problem until a couple of nights ago. I switched to 25.1 on the Vizio and then pushed the Guide button on the remote. This locked the remote and TV controls. On the Vizio simply unplugging the TV will cure the problem.

So after seeing this behavior with the Vizio and reading this post with mentions of the Guide being a possible problem on the Aquous I changed the menu option to not show the guide when changing channels. Good thought, but it did not solve the locking problem on the Aquous. I have no idea technically what is causing the problem except it seems to originate from 25.1's signal.

Putting your town and state into TVFool I find that 25.1 is listed as a -61dB signal with 2edge path. That is a very weak signal and should be requiring you to do a lot to get it. Do you have outside antenna on a high tower and yagi antenna pointed roughly to the north?

I have had no problem with this channel since the switch to digital and I have owned the Aquous for more than 2 years. The problem started in December. I have an indoor antenna.

Hum, then talk to the station engineer--sounds like the channel has a problem and it is not your set.

Older thread now, but this particular issue has been driving me nuts. I live in Louisville, north and west of Denver. Bought a Sharp Aquos set in Octobr and promptly hooked it up to an outdoor antenna pointed as antennaweb.org instructs. I get all local broadcast HDTV channels quite well, including 25.1. And sure enough, when the TV lands on that channel it will lock up as described in this thread.

The wrinkle with me is that if I leave the set off, and plugged into the antenna, the set's front touchpad locks up after 5 or 6 days on average. The touchpad simply does nothing. Unplugging the set and plugging it back in immediately restores function.

I had Sharp come out and swap out the touchpad component, the ribbon cabling between the touchpad and the mainboard, and the mainboard. None of this solves the issue. Incidentally, the technician warned me about the local 25.1 problem and advised me to program that channel for 'skip' which I did.

Knowing that the set is prone to lockups due to this issue, I experimented by removing the antenna connection from the set entirely. Guess what? No more lockups. The set has gone a month without lockups. I do have a cable presence where i have the set so i am now using cable connection to get just clear qam channels....and again, no lockups.

Something on the airwaves in Denver is causing these sets to lock up, and apparently, it can even happen when the set is 'off'. I could call Sharp about this and ask about a fix, but I have a feeling they will think i am insane...

Incidentally, the model number of the set is LC52LE830U.

This is an update to the problem. A few weeks ago I accidently pushed the Guide button while watching 25.1 on the Vizio and the channel did not lock. I tried 25.1 on the Aquos and it did not lock. They changed something at the station.