I just inquired a Sylvania Set from 1981, I know, imported, and a bit more modern than most care for on here.. I noticed after powering on and about 10-15 seconds later the high pitch ringing gets much louder than normal coming from the HV section somewhere, when on a station with no reception, it goes away, when adjusting the brightness low, it gets louder.. Would anyone know if this is a issue?

It probably won't hurt anything. It's most likely a loose flyback core and you may be able to silence it by using some silicon to hold it in place. Just use caution when working around the flyback or yoke. There are voltages there that will get your attention. If this is an '81 model, it probably uses an E32 chassis. '81 was also the year that NAP bought the Sylvania and Philco names from GTE; so, you could have a "last gasp" GTE set or an "early" NAP set.

Sometimes re-flowing the solder on the pins on the flyback can help, if this is a chassis where the flyback is surface mounted on the PC board.

Here are some pictures.. It looks close to the mid 1980s Sylvania Super sets, I'm guessing an early NAP.. The flyback is mounted on the Board.. Does this hold voltage after being unplugged or is it only the picture tube?

those are very good performers!solder joints around flyback or loose core.that will fix it up.sharp,sharp. black matrix crts produce a fine picture.among the best picture of all time

I notice it has a bit of a brown tint, more likely the red is a bit high, I've fixed issues like this before by adjusting the red, green and blue pot switches, But I don't know if I'm doing that to make up for week guns or bad circuits.. I could get my sencore out and test each gun..

I agree those early, mid 1980s super sets put off a great picture.. We had one in the family that was bought new back in 1985, it lasted till 1993 when the tuner went out..

Is that an old hospital set? Back in the '80's, the local hospital had some of these and they used a heavy 3-wire AC cord. There was a socket on the rear of the set for the remote pillow speaker and the TV's would also work with an IR remote.

Your chassis was actually a "transition" chassis. They came out while GTE still had Sylvania and they stayed around well into the NAP era. I used to have a 19" GTE-Philco from early '81 with this chassis. I tossed it when the CRT got too weak to use.

I don't think this set is, It doesn't have any socket to connect an IR Remote.. Would you recommend a discharge of the crt before going around the flyback area?

Tightening those two hex nuts a bit may quiet it down. Don't tighten too much 'cause that's a powdered iron core. oc(Bill)

take an insulated alignment tool and touch the ferite beads on diodes, resistors, etc. Something is vibrating. If you find a bead loose, use candle wax to secure it. RTV may trap moisture.

I re soldered and sanded all the joints to the flyback and still does it, I notice the brightness changes depending on the image that shows up on screen..

I just tightened two hex nuts and the set is much quieter now. I was only able to get a nudge, even doing that i heard a crunch noise..

I let the TV sit with the cover off and let it run for hours and hours and the symptoms all went away, TV must have been stored without use for a long time, I adjusted the red blue and green pot switches to normalize the colors, red having to turn down alot. after a few hours of running I had to turn the red back up, I think tells me the CRT cooked it's self back to life. I brought out my Sencore CR-70 and I'm looking in the 1992 CRT number listing booklet and the number of the tube is not listed, it's a MV19VLEP22...

Drop the MV prefix and look it up as a 19VLEP22.

caps could be starting to dry up as well.

Found it, had to drop the MV.. I tested all guns and all read well into the green, all seem to read the same, none weaker than others.. I put the set back together and seems to be working like a charm.. Thanks for the input radiotvnut..

I had a similar one once and wish I still had it.personally i'm a big fan of gte sylvania's the 70s/pre-NAP ones especially

I notice these sets have a common tuner problem, this set hooked to the converter box and is on 3. The channel goes out to complete static periodically and have to move the channel up or down and than back to 3..

Another trouble spot (if I remember that chassis) that will make you scratch your head is no color. There are two (I think 150K) resistors side by side near the flyback that open up. Took me a long time to find them. Other than that, these were good sets!

The high pitched ringing you hear is from the flyback as it has a loose core. We would fix that by driving a small thin wood wedge between the core and the windings (toothpick works good many times) and then you can RTV it. Sometimes you can tighten the two nuts on the FB holding the core but if you overtighten them, you can either break the core or the soft threaded rod that the nuts connect to. The noise doesn't hurt anything but it sure is annoying.
The flyback doesn't hold any charge, just the CRT but most of the later sets like yours has a bleeder in it that it won't hold a charge very long after set is turned off. Still a good idea to short the anode to ground of you are around it.