Quote:
Originally Posted by RitchieMars
As for the sound...
It works but it's VERY buzzy. All of the cable channels come through with a lot of loud buzz and distortion that overpowers everything. The buzz gets louder when the picture gets brighter. The VCR fairs a little better, but the buzz is still obnoxious. Plenty of volume... the tone control works nicely... but the noise is horrible. I tried adjusting the "buzz control" on the back and it only made it louder. 
UPDATE:
I can get the buzz to go away with the VCR playing by turning the screen register up and tweaking the fine tuning and buzz control. This only works with the VCR, though. The cable channels still sound distorted beyond belief. I guess it's something about the raw cable signal. I don't have a converter box, just the VCR. I'd try the DVD but the only DVD player I have uses the red, white, and yellow connectors. This tv came with a coaxial adapter so I've been using anything that plugs in that way. |
The buzz is caused by the sound carrier being turned off by the video peaks at white in the picture. White in the video image coincides with minimum TV channel carrier, and if an IF amp is misbiased, the carrier can momentarily disappear. Most TV sets use an "intercarrier" sound IF system. As TV sound is on an RF FM signal 4.5MHz above the picture carrier, it shows up at the video demodulator as an FM signal at 4.5MHz. But if the picture carrier disappears so does the 4.5MHz FM sound signal. This disappearance ends up sounding like a buzz, as the peak white details in the video image repeat at the vertical rate, 60Hz.
So there may be a weak tube, bad resistor or such in the IF strip. The audio amp is likely not a fault. But sometimes some TVs used the audio output circuit as an IF strip voltage source, they'd place the audio output circuit in series with the bank of tubes in the IF strip. But your TV probably doesn't do that, else you would have gotten no reception with the open primary of the audio output transformer.