Is my TV cactus?

[AstralTraveller (David)]

I'm looking for a bit of advice from any electronics techs out there.

My TV was bought in 07 or 08 and has had an intermittent problem for at least 6 months. Mostly, the picture freezes and the sound stops, though occasionally it goes 'jerky' with the picture updating every 0.5 to 2 sec. The only way to reset it is to turn it off and on at the wall. Rarely it will freeze as I change channel and it this case it will restart itself after about 1 minute. Generally it will be OK for the first 30 minutes after turning it on. Some nights it only fails every 15-20 minutes or so other nights (especially during a good show ) it can fail every 3-5 minutes.

I'm assuming it is the TV and, given its age, replacement would be the only option. However, before I part with the hard-earned I'm wondering if it could be the areal. I imagine areal problems would present as pixelation or dropout and be correlated with weather conditions (eg worse during storm or heavy cloud), something I haven't noticed. I also haven't noticed the problem being different on different stations but since I spend 99% of my time on ABC or SBS perhaps that isn't surprising.

Could it be areal (or cabling) and how would I check it?

[sharkbite]

Could be an aerial problem...

Digital TVs give a "perfect" picture even with a degraded signal,
up until the signal is so bad it drops altogether.

Most digital TV's have a signal strengh & quality meter buried in the settings menu somewhere....
Couldn't tell you exactly - don't know what telly you have ;-)

If it works ok with (for example) a DVD player, you could keep it as a backup/games room/super duper pc monitor....

good tellys are a bit cheaper nowadays ;-)

[John0z (John)]

Most TV's will often suffer from power supply failure sometime in their life. To check if it is something else - I would suggest when it plays up, to press the Menu button. If the Menu screen is also broken up like the picture then I would say it isn't the antenna, but could be power supply or main system board. On the other hand, if as suggested, it works with AV input but not on TV tuner - that it could be a tuner problem. Typically if the picture goes and the sound stays on, it can be power supply too, but more likely the backlight circuit if LCD, or the Y/Z drivers for plasma.

[julianh72 (Julian)]

It sounds like the signal strength / quality is marginal - this could be due to damage to the aerial or antenna cable - or even the direction the antenna is pointing. As sharkbite says, the Menu of a digital TV will tell you the signal strength and quality you are receiving on each channel - if it is low, you can get pixellation, freezing, sound drop-outs, etc.

Do you have a set-top box or PVR or similar which gives a better, more consistent signal? You will often find that the tuners of various devices will have quite different sensitivities, so one device can give a very poor picture, while another has no troubles at all when plugged into the same antenna point. You can pick up cheap HD STBs for under $50, so it is a pretty cheap experiment if you don't already have another device you can test.

[Renato1 (Renato)]

There must be someone you know who has a small digital TV that you can borrow for a couple of hours, or you may even have an old set-top box that would do the trick too.

Set the borrowed TV up where your TV currently is. If it does the same, the problem is with the reception. Or set up the Set-top box, and feed its output into your TV's AV or HDMI input, and see whether or not it does the same.
Regards,
Renato

[Baddad (Marty)]

From your description it sounds very much like the TV power supply.
I used to repair TV's and other gizmos.

I doubt if you can initiate the menu when the set goes down.
Yes pixelation occurs with weak signal. As in antenna problems
The power supply usually or nearly always has a safety cutout device.
Try running a DVD video. I bet the problem will still be there. That takes the aerial out of the equation.

It may not be just the power supply. It may be another problem triggering the safety cutout from overload.

One for the repair shop or if its a small screen, replacement.

Cheers

[wasyoungonce (Brendan)]

If you try another source...and it's still present. Then I'd doubt PSU.

If it is not present then its possible one of the the PSU voltages is low. 33V is is used a lot in tuning sections. That said these modern TVs monitor their output voltages for fault, but not all voltages. Could even be noise on a voltage line.

TV PSU have been a plague since way way back in CRT days, I was fixing TVs back in 1980's.

These modern TVs/LCD PSU also fail. I fix many and you would be surprised at it's always the same components, "switchmode power supplies". Mainly due to the capacitor plague on not only computers but all electronics, but also due to high ripple demands on capacitors.

Anyway I digress....try the above. Try a TV repair they don't charge much if it's a switchmode issue (bread and butter repairs) but if it's something else...well the TV is quite old compared to todays new generation stuff and todays equipment is cheaper and better. A Tech could spend too much time fault finding than the cost differential saved to but a new one.

Aldi have a 55" LCD $599 (11 oct sale, my store still has them). I have 2 Aldi TV, one running since 07...! Cannot complain about them.

[GUS.K (Ivan)]

It sounds like an antennae problem, signal freezing and pixilation are an indicator that your signal is close to the digital cliff. A digital picture can look perfect even if the signal quality is low, and replacing the TV won't fix this,you need to get a TV tech with a good digital meter to see where the problem is.

[tlgerdes (Trevor)]

How big is the TV? If it is less than 55" then it is cactus and time to get something bigger.

[AstralTraveller (David)]

Thanks for all the replies. Last weekend was bedlam at my place so I've just got back to this. I reckon it is the TV, something in the tuner. There is no meter in the TV so I tried removing the areal cable. As it got lose the picture came and went a bit. After the cable was removed the screen went black and a dialog box appeared saying 'Weak or absent signal'. Re-inserting the cable got the picture back. What I see when it fails is the picture freeze and the sound stop. The TV then will not respond to the remote and only an off/on at the wall restores it.

To me that sounds like it must be in the TV. And the reason I think it is the tuner is that DVDs seem to play OK. It went 2 hrs without fail and my wife (the movie watcher) thinks it's always OK on DVD.

In the size I need (ie what fits in the space I have) direct replacements are about $500 though a smart TV, which is what I'd get, is about $800. I think any repair would run to >$200, probably much more. I think I'm better off with a new one?

[taminga16 (Greg)]

IS MY TV CACTUS?

YES!
Move on.

[acropolite (Phil)]

If it runs OK from a DVD player simpy buy a cheap Set Top Box and use that for tuning.

[mswhin63 (Malcolm)]

Originally Posted by acropolite

If it runs OK from a DVD player simpy buy a cheap Set Top Box and use that for tuning.

Definitely appear to be signal reception. Changing to a STB may make it worse though until the antenna is replaced. After that it may work well.

A PSU problem will occur on everything including DVD and anything else.

How old is the antenna.

I used to repair TV's as well and also installed antennas till my knees started to give up.

[tlgerdes (Trevor)]

Have you retuned your TV in the last 6 months?