View Full Version : looking for perfection!


radio nut
05-11-2014, 05:59 PM
Once again I am inclined to ask a question about a very slight sound buzz.
I went through my Muntz again, readjusted everything and still.......a very slight buzz in the speaker.
Rechecked lead dress, tubes even ran each adjustment all the way either direction and still.....buzz. Not bad, hardly noticeable, but I would like perfection. A proper recalibrate, ok without a scope but using the vtvm calibration set up on the diagram and its still there.
oK, "IF" I remember correctly someone had stated that a cheaper dvd player could cause this.
Am I looking for perfect sound where it's not going to happen?

old_coot88
05-11-2014, 06:15 PM
Perfectionism is the manic form of fuddyduddy-ism.

:D:D

Username1
05-11-2014, 06:42 PM
Perfectionism is the manic form of fuddyduddy-ism.

:D:D

HA ! HA !

That one is pretty good ! ! !

-----------

So is the buzz there with all signal sources...? If so it's the tv, if not it's
yer DVD player, possibly....

Could be the elmer converter between the vertical antenna, and the horizontal
receiverator...

radio nut
05-11-2014, 07:27 PM
I could try disconnecting the dvd player and running it with the digital converter box I just got....... thanks!

old_tv_nut
05-11-2014, 07:46 PM
Buzz on certain video or constant buzz?

radio nut
05-11-2014, 09:09 PM
seems to come and go but I can't pin down a pattern for sure. yes it buzzes with text on the screen but sometimes seems to be just a bright image and it buzzes.

radio nut
05-11-2014, 09:09 PM
not constant

radio nut
05-11-2014, 09:13 PM
Was just watching a documentary on the history of old trains and the screen is showing old film and as an the scene changes from one train to another and the background is a lot brighter it starts buzzing

earlyfilm
05-12-2014, 07:01 PM
Was just watching a documentary on the history of old trains and the screen is showing old film and as an the scene changes from one train to another and the background is a lot brighter it starts buzzing

OK, need a second test. Remove your antenna connection and short the set terminals while the set is buzzing. If the result is no buzz, then do the test that I proposed in the 9th post in your old thread.

http://www.videokarma.org/showthread.php?t=259882

This test did not pinpoint the problem before since there was another cause for the buzz then.

If this tests now reduces or eliminates the buzz, then the problem is signal overload.

The most obvious cause is too strong a signal.

It also can be caused by misadjustments of gain setting (including local / distant switch) or gassy tube in the tuner, IF, or sync tubes. Most Muntz sets did not use them, but if your Muntz has a tube labeled either AGC or AGC Keying, that is a real possibility. If it has keying, (and only if) then also suspect the tube that provides the signal that is keyed, which often is the video output tube.

James.

KentTeffeteller
05-12-2014, 09:00 PM
Muntz is a verb! To Muntz is to reduce any circuit to the minimum necessary to function. aka Minimalist engineering. Perfection they don't do. Muntz is basically Good Enough to do the job.

radio nut
05-13-2014, 12:56 PM
Muntz is a verb! To Muntz is to reduce any circuit to the minimum necessary to function. aka Minimalist engineering. Perfection they don't do. Muntz is basically Good Enough to do the job.
I feel compelled at this point to bring up something in order to ask a question.
I was given a Sam's book on TV circuits and explanation from 1955. In many cases they had examples of new circuits, which very closely resemble circuits in my Muntz.
Is it possible that Muntz was ahead of his time? If I can figure out how to do it I may post pictures of the NEW circuits shown and my Muntz diagram , from 1950...5 years ahead of the Sam's book.

radio nut
05-13-2014, 01:00 PM
OK, need a second test. Remove your antenna connection and short the set terminals while the set is buzzing. If the result is no buzz, then do the test that I proposed in the 9th post in your old thread.

http://www.videokarma.org/showthread.php?t=259882

This test did not pinpoint the problem before since there was another cause for the buzz then.

If this tests now reduces or eliminates the buzz, then the problem is signal overload.

The most obvious cause is too strong a signal.

It also can be caused by misadjustments of gain setting (including local / distant switch) or gassy tube in the tuner, IF, or sync tubes. Most Muntz sets did not use them, but if your Muntz has a tube labeled either AGC or AGC Keying, that is a real possibility. If it has keying, (and only if) then also suspect the tube that provides the signal that is keyed, which often is the video output tube.

James.

I did do that test, but I do not remember exactly the results. I THINK that all I got was snow and weak picture..... but no buzz....thanks for reminding me!
I will re test ans post results maybe this weekend.
Thank you again!

radio nut
05-18-2014, 12:31 PM
Ok, after testing, here is the end results.
I added a attenuator( 6 db, from fair radio) and it was better.
I switched it to the digital converter box/ ant and there is zero buzz.
So if I did this correctly my problem was a combination of cheap dvd player and the tv being overdriven also.
Thank you everyone who chimed in!

radio nut
05-18-2014, 03:57 PM
Heck, the picture is even cleaner!

bandersen
05-18-2014, 06:01 PM
That's great news. I'm glad it was a simple fix.