Sony TV buzz sound through headphones

[Fizzycapola]

Probably not fixable. I don't know for sure though. I don't want to replace it with an LCD
just yet, it's the best solution I have for playing my old 4:3 games consoles and stuff,
but if it's going to keep buzzing who knows.

I see those ( perhaps just 1?) Jamicon caps sitting a bit close to the headphone out.

All the othe parts of the TV look to be Nichicon or Rubycon.

[Krankshaft]

Re: Sony TV buzz sound through headphones

If the sound through the speakers is fine first check for cracked solder joints on the jack.

When you plug the headphones in the pin on the headphone jack engages a switch inside (a strip of springy metal) which disconnects the speakers from the amp to shut them down.

[i4004]

Re: Sony TV buzz sound through headphones

if you're watching sd lcd is crap and cannot beat image qualit of crt.

it should be easy to fix, as krank says.

check jack...if soldering is ok, spray some wd40 to clean it inside.
(thinksinmg about wd40 it's probably best to spray it a bit into something that can be applied easier than a fucking ton of spray......)

good thing you've blacked-out the serial...now you're completely safe!
lol!

[Krankshaft]

Re: Sony TV buzz sound through headphones

Not to mention plasma and lcd still haven't gotten even close to the Contrast radio of a good CRT.

[Fizzycapola]

Re: Sony TV buzz sound through headphones

Wouldn't that be evident by jiggling and shaking.

The hum in question is not affected by volume also. And is constant, not like the standard hum affected by volume level. It particularly takes away the magic when you're watching a movie and theres a quiet scene. The reason I mention the Jamicon's, is they're popular for audio, but also known to have issues.

I'll measure the Jamicons soon. At the moment all my tools are in a dump somwhere because a family member, who doesn't value anything of mine no matter how much it costs, displaced them. So awaiting new tools atm.

[i4004]

Re: Sony TV buzz sound through headphones

either way, you shoudl know that same chip is making sound for headpohones and speakers, so if oneis ok, it means chip is ok...

[Krankshaft]

Re: Sony TV buzz sound through headphones

Did you try pulling the cable line then select one of the video outputs to get a quiet scene (if your TV is older and still outputs the static noise)?

If it stops then you have a ground loop problem. I recently needed a ground loop isolator when I installed a video capture device to my game console the loopback function caused annoying hum.

Plugging in alot of devices with different ground potentials causes this.

By all means the caps in the audio amp circuit could be the problem. Be sure to identify where the audio amp is to locate the caps in it's circuit.

A low hum could be the coupling capacitors (the on the output of the amp right before the speaker).

A loud hum is usually caused by dried up filter caps.

[Fizzycapola]

Re: Sony TV buzz sound through headphones

Ok I did some more basic user testing and wrote some things down.

These are additional to the low constant buzz. This buzz I think does come through the
speakers too, but it's more apparent on headphones because they diminish the open air
background sounds and are more sensitive.

In addition to the above:

Selecting analogue TV station then proceeding to AV1. Can still hear faint sound from
TV station.

Selecting non tuned channel then AV1, no TV station sound.

AV2 ok.

AV3 most buzzy as well as faint watery noises like highly compressed mp3 artifact
noises, moving volume up or down results in a fairly loud sound like text being displayed
line for line on a screen in a sci-fi movie.

thanks again for your advice Krankshaft & i4004

[i4004]

Re: Sony TV buzz sound through headphones

av3 sounds like ground loop.

so use av2...hehe...

to troubkeshoot it it seems it would be wise to try to establish any differences between av2 and av3...(easier with el. diagram of your tv)

to troubleshoot ground loop:
at first connect just tv to (unpowered..heh) antenna, and see how things are.
then add your devices....when does humming begin?
does av3 hum with all devices, or with just some?
you get the idea...

[zandrax]

Re: Sony TV buzz sound through headphones

Selecting analogue TV station then proceeding to AV1. Can still hear faint sound from TV station.

Selecting non tuned channel then AV1, no TV station sound.

Tell me Fizzy: is AV1 a Scart (or EuroAV) plug connected to a videorecorder, be it VHS or DVD one? I ask this because the Scart carries both Audio output and input: the VCR may be configured to show its Scart input which is the TV channel you're watching out. This explains why you don't hear any sound if you set a blank channel on TV: the VCR shows the same blank channel.
This "feedback" channel was used in early pay-tv or external teletex decoders which captured signal from TV through Scart, decoded it and showed the decoded output on TV screen; if you don't use it, you can remove the related pins on the scart cable (tv side) to stop the ground loop. IIRC, the composite input is pin 20 and audio inputs are pin 2 and 6: you can check the pinout here [1]. Read the Wikipedia entry [2] too.

AV2 ok.

Unconnected?

AV3 most buzzy as well as faint watery noises like highly compressed mp3 artifact noises, moving volume up or down results in a fairly loud sound like text being displayed line for line on a screen in a sci-fi movie.

On my father's Sony KV-29FX30E AV1 and AV2 are both Scart plugs and AV3 is connected to the S-Video and Composite inputs for video, 2 RCA for audio on the front panel. Some TVs have a lateral panel which is the same: check these connections.

Zandrax

[1] http://pinouts.ru/Home/Scart_pinout.shtml
[2] http://en.wikipedia.org/wiki/SCART

[Fizzycapola]

Re: Sony TV buzz sound through headphones

That was with nothing connected. Your guesses are all correct; AV3 SVHS / Compo.

Well I found out the sound output from most of my devices, I can directly connect to my headphones, if I use ones with volume dials, makes a good workaround, plus sound is better quality going through less devices.

Thanks for your posts I'll report back if I make some progress on this.

[zandrax]

Re: Sony TV buzz sound through headphones

That was with nothing connected.

So the feedback channel on the scart connector isn't the culprit. Sorry, I have no ideas now.

Thanks for your posts I'll report back if I make some progress on this.

Keep us updated.

Zandrax

[Krankshaft]

Re: Sony TV buzz sound through headphones

I'd say this would qualify as a "tough dog" problem.

I had a puzzling problem with an audio amp IC on a cheap 5.1 sound system. It used basically dual channel OP amp based ICs to amplify the sound they were designed for audio though. The right rear channel was dead so I replace the IC that controls it. I power it up the Right Rear is fine now but the center channel is dead.

The center channel is on it's own IC it's a dual channel but only one channel was in use. I was puzzled especially since I didn't mess with that IC.

I replaced the center channel IC for the heck of it and it was still dead .

Turns out when removing one of the ICs I accidentally scraped off a tiny piece of copper leading to the ground trace of the IC. So I soldered a jumper wire and and scoped out the output of the amp.

Bingo we have sound !

Stay on it and I'm sure you will find the problem.