Predicta: My first official Restore

[Phil Nelson]

Originally Posted by 6GH8cowboy

The sync buzz is very prominent on graphics. Is there a known mod for this

My 17" Siesta doesn't buzz noticeably when viewing normal content. Based on that unscientific sample of one, I'd say you should be able to get reasonable audio without circuit modifications.

The 9L37 chassis used in 21" Predictas has a buzz control -- a potentiometer on the cathode of the audio detector -- where your set has a fixed resistor. If you feel like playing around, perhaps you could substitute a little pot there and see if it helps.

Regarding the couplates (hybrids, networks), I guess it's a judgment call how many you want to replace, if any. I replaced one in my first Predicta and three in my second Predicta. These were replaced to cure problems that I observed after finishing a basic recap. The couplates that I didn't replace are still holding up years later; your mileage may vary, of course. One downside of shotgunning all of the couplates is that you'll make a crowded board even more crowded.

You can read more about the second project (a Siesta) here:

http://antiqueradio.org/PhilcoH3412L...Television.htm

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html