jlh@loral.UUCP (The Mad Merkin Hunter) (06/16/88)
I'm not sure if this goes here or not but it's better than misc.headlines.
My TV set has a loud buzzing whenever white text is displayed on the screen.
Also white picket fences, white borders, or any verticle white whatever
that appears on the screen. The more verticle edges that are displayed,
the smaller the characters/boxes, and/or the whiter the color the louder
the buzzing. I can't even stand to watch Jeapordy anymore. This problem
first reared it's ugly head with mild buzzing about 6 months ago and it's
been getting steadily worse.
The TV is a JC Penny, probably about 10 years old (I bought it used 8 years
ago). I think it's a 19 inch, I know it's a table top model. So can I fix
it myself by tweaking some of those nifty knobs in the back, or do I have
to send it to the shop?
Jim
"I think I'll take up smoking"
--
Jim Harkins
Loral Instrumentation, San Diego
{ucbvax, ittvax!dcdwest, akgua, decvax, ihnp4}!ucsd!sdcc6!loral!jlhlkraft@hpccc.HP.COM (Lyle Kraft) (06/20/88)
Sounds like some tweaking of the sound detector quadrature
coil is in order.
Scenes with a lot of vertical detail generate a large amount
of high frequency video signals which interfere with the
sound subcarrier. Alignment of the sound detector becomes
more critical under these conditions. Sometimes the sound
detector will drift out of tune with age or heat and cause
this problem. The worst that may be wrong is that the video
IF strip is out of alignment, but this is highly unlikely.
To adjust the detector, find the correct coil in the sound
circuitry, either a metal can or a plastic tube with wire
wound on the outside, and find the correct alignment tool
to adjust the internal tuning slug. Tune you set to a strong
station with a program showing a lot of detail, like
Jeopardy :-) , and adjust the coil for maximum volume/minimum
buzz.
If your set has the "works in an IC" type of sound system, ignore
all of the above.sheperd@raider (Charles Cain) (06/21/88)
In message (1791@loral.UUCP), jlh@loral(Jim Harkins) writes: >My TV set has a loud buzzing noise whenever white text is displayed on >the screen... What you are experiencing is what we in the industry call sync buzz. The problem is that the white level is of such a high magnitude that it is getting into the synchronizing pulses and is being introduced into the audio portion of the TV signal. Probably what has happened is an amplifier in the front end of the TV set has gone bad and has too much gain for the rest of the amplifiers in the set. A couple of questions though. 1) does it do it on ALL TV stations in your area, and 2) have you tried playing with the controls on the front of the set. If it is only on 1 station, then they have a serious problem. If not, then it would probably be in your best interest to get a new set since it is 10 years old and the capacitors in it will start drying out right about now and you will have more problems like this. Hope this helps you out Jim. Charles R. Cain, Broadcast Engineer,WTVF-TV Nashville, TN a/k/a sheperd@raider.UUCP Disclaimer: These are my opinions after YEARS of learning them. --- * Origin: Raiders Roost: Mid TN's FIRST FIDO<->UUCP GATEWAY ! (Opus 1:116/12) SEEN-BY: 116/12 -- ______ / / * Middle Tennessee's FIDO<->UUCP Gateway * (615) 896-7964 /_____/ ___ o ___ ___ ___ * Murfreesboro, Tennessee * / \ /__/ / / / /__ /__/ Bob Reineri - System Operator _/ \___/ /__/__/__/__/__ __/ \_ Mark Bailey - UUCP Project Mgr. UUCP: !{ames,osu-cis,rutgers,decwrl,mit-eddie}!killer!raider FIDO: 1:116/12
berger@clio.las.uiuc.edu (06/22/88)
You should also examine your AGC gain. Too high a setting can result in
the white-text buzz.
Mike Berger
Department of Statistics
Science, Technology, and Society
University of Illinois
berger@clio.las.uiuc.edu
{ihnp4 | convex | pur-ee}!uiucuxc!clio!berger