HITACHI C32W511TN - Rattling noise?

[CiaranMcNulty]

Hi,

We recently bought a HITACHI C32W511TN from http://www.cheapesttv.co.uk.

It was a pretty cheap set for the price (£499+VAT), but there's a slight problem with it.

Sometimes while we're watching it, there's a fairly lod high-pitched whine, which sometimes sounds almost like a rattle?

This happens even when the sound on the set is muted.

Anyone know what this might be? Is it normal, or do we need to send the set back?

Thanks,

-Ciaran

PS - there's something glowing inside the TV, near the back. I assume this is some sort of bulb, or even a vacuum tube? Should there be any eerie glowing components in my TV? ;-)

[Paul Buglass]

Ciaran,

The faint red glow down inside at the back is the electron gun heating elements at the back of the CRT. It's perfectly normal to see this red glow through the glass of the tube and nothing to worry about (provided it's not accompanied by a burning smell and whisps of smoke of course ;-) ).

As for the high pitched sound almost like a rattle at times, well since you hear it with the sound muted, it's unlikely to be just a loose part rattleing due to sympathetic vibration and resonance with the sound at high audio levels.

It's sounds as if it may be the 'line transformer' which provides the scanning frequency signal. Sometimes the laminated metal sheets which make up the iron core of the transformer can be loose and can vibrate, at a sub harmonic of the operating frequency, in the audiable range, (some sensitive people can hear a high pitched whine from almost any TV, while the rest of us can't hear a thing).

Often this can come and go as the transformer heats up and the metal core changes shape very slightly, thus restricting the vibration of the loose bits. The cores are normally coated in varnish/resin to bind the separate metal sheets together to stop just this sort of resonant vibration.

The gist of this is that if it is loud enough to bother you in normal use, then I would raise the "unacceptable loud whine" as a fault with the set, and insist on a replacement or repair.

Hope this helps.

Best wishes

/Paul B, York, UK.

[CiaranMcNulty]

Originally posted by Paul Buglass

The faint red glow down inside at the back is the electron gun heating elements at the back of the CRT. It's perfectly normal to see this red glow through the glass of the tube and nothing to worry about (provided it's not accompanied by a burning smell and whisps of smoke of course ;-) ).

I can't see the glow through the CRT, I can see it through the grill on the top of the set... it's at the rear centre of the circuitry.

As for the whine, then it's not loud enough to bother me in real life. I was just a little concerned it was a sign of a more serious fault. Our warranty is only 90 days, so we need to be sure it isn't going to burst into flames in 4 months' time!

Thanks for the advice - nice to know its not uncommon ;-)

[Paul Buglass]

I didn't mean through the glass as in the TV screen. I meant through the glass neck of the tube right at the back when, as you say, you look down the grill in the rear cabinet. If you could see it through the screen something would be seriously wrong with the TV !!!!

A quiet, almost inaudible whine is normal, but if it's loud, and prominent enough to bother you, then maybe you should do something before the 90 days is up.

Best wishes

/Paul B, York, UK.

[CiaranMcNulty]

Originally posted by Paul Buglass
I didn't mean through the glass as in the TV screen. I meant through the glass neck of the tube right at the back when, as you say, you look down the grill in the rear cabinet. If you could see it through the screen something would be seriously wrong with the TV !!!!

Heh.

It doesn't look like it's inside the tube, I'll have another look later.

A quiet, almost inaudible whine is normal, but if it's loud, and prominent enough to bother you, then maybe you should do something before the 90 days is up.


Well I can always hear a whine when a TV's on, but this is a lot louder than normal (although when the volume's turned up it's not that noticeable).

I'll see what my housemate (who actually bought the TV!) wants to do.

Thanks again for the advice.