Headphone jack mod

[lnx64]

Only annoying thing though is I can hear the 60hz hum in the headphones even with the volume turned down.

[Jon A.]

Uh oh, sounds like tying the resistor to ground may have caused a ground loop issue. You might need to move that resistor between the jack input and headphone output as I originally instructed.

[lnx64]

Actually, I forgot to mention, the speaker normally does this on it's own too :/ For some reason the TV just has it in the audio signal.

If I feed the TV a PAL video signal, it becomes a 50Hz hum, so it's coming from the vertical retrace.

[Jon A.]

Hmm, bad filter cap somewhere I suspect. You could have a cap that's completely open, causing the vertical retrace to cross-couple into the audio circuit. One time, when I was a lot younger and didn't know nearly as much about what I was doing, I over-volted an under-dash 8-track player, which soon blew the side out of a cap. Good thing the top didn't blow out, I was looking into the player when the cap blew. Running it without the cap caused noise in the audio.

[lnx64]

This is the buzz I hear btw.

http://www.mediafire.com/listen/uf2b...yc1/tvbuzz.mp3

This has happened on the TV since I got it through it's built in speaker. Does it on UHF and VHF. In the audio I'm turning the volume up and down. When cranked up all the way, the noise changes to a weird space ship sound..

[Jon A.]

I can't hear anything that I would consider out of the ordinary, even with my computer's main volume control and the Quicktime player volume all the way up. Of course I have only one tiny speaker, and it's built into the tower, which of course is on the floor. I leaned in closer to it though, still couldn't hear anything.

[lnx64]

There's definitely a buzz.. Shows up on my oscilloscope and Audacity..

[Jon A.]

Unfortunately I can't think of anything else that might be wrong. I suppose the bad/open cap, if any, could be in the audio circuit as well. Sounds like you have a good complement of equipment there. Should set yourself up with an ESR meter if you haven't already.

[lnx64]

Don't have one sadly.

[Chip Chester]

Might try playing with the video signal to make the buzz go away. Disregard how it looks, but turn down brightness, color etc. to see if it makes a difference. Extreme levels in video have been known to cause audio artifacts. The results of this test will focus your investigation.

Chip

[lnx64]

Hmm, it didn't do anything.. No change at all.

It's likely going to be a bad cap..

[zeno]

I am very proud of you ! I never had skill with tools
so never did one like that. Looks factory, wickid pissah !!

73 Zeno

[zeno]

Originally Posted by lnx64

Hmm, it didn't do anything.. No change at all.

It's likely going to be a bad cap..

Sounds 60 hz to me but I cant hear well. Can be picking it up
from the vert or power supply. Try moving the speaker wires,
yoke & vol. control wires & see if it changes.
Beyond that its prob. a cap. But most if not all of the audio
runs off a scan supply so you would get a very high pitch
if the supply had crap on it. May end up being a job
for a scope...........

73 Zeno

[lnx64]

I think it's from the deflection because on a scope i see both 15khz and 60hz noise, this would then be both horizontal and vertical issues and when i give the tv a pal video signal the 60hz noise becomes 50hz..