[winkydink]

I recently acquired a Philco 51-T1601 Television which has been recapped and otherwise electronically restored.

I am having a problem with some intermittent buzzing sounds in the audio.  I will describe below, but the bottom line I am looking for is - is this a tube problem, ground loop problem, over saturation problem etc.  and more importantly, how do I attempt to fix.

The problem:

I have the TV connected up to an external digital tuner and also blue ray player.  as follows:


Blue-ray player --> RCA to RF   ----> Digital Tuner            ------>  TV
                              Converter            (with RF IN & OUT
                              (modulator)          ports)


When I play the TV with just the digital tuner, the audio is fine (for the most part).  Occasionally on some scenes images you might hear a low volume buzz but for the most part the audio is crisp and clear.

When I use the Blue ray player, depending on the disk I am using I will get a much louder buzz that will occur for say 15 seconds at a time (with audio from the disk still playing and not distorted) and then for 15 or 20 seconds there will be no buzz and the audio will be fine.  This will repeat non-stop.

Some DVD disks this problem will be less prevalent.

I have not tried a different DVD player yet or tried a different RCA to RF modulator.  I may attempt those in trying to isolate the problem.

Any ideas what this could be.  Tubes, cables, modulator, ???

Looking for some simple things to try first working up to the more difficult.

Thanks in advance for any help with this.

[TV MAN]

Sounds like macrovision (copy protection) on your dvd. Some old TVs had a little sync buzz in the sound that will change with the scene. Some have a buzz control, sometimes you could slightly adjust the AGC to help, but a soft buzz on certain scenes may be Normal.

[WallaceRoger]

Ahh, good old Macrovision.

I used to have a signal stabilizer/booster from Radio Shack years ago that worked pretty well to remove the Macrovision coding junk.

[Radioroslyn]

Sounds like macrovision (copy protection) on your dvd. Some old TVs had a little sync buzz in the sound that will change with the scene. Some have a buzz control, sometimes you could slightly adjust the AGC to help, but a soft buzz on certain scenes may be Normal.

I believe if the picture or scenes have more black in it it tens to increase the sync buzz. Going from a fairly light pic to a darker one is when is the most noticeable. My '50 RCA has it and it's a bit of a balancing act w/the fine tuning vs the audio level. By using the fine tuning I've gotten better but is still there. I'm not really a TV guy but have serviced a few over the yrs.