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  #61  
Old 05-12-2018, 07:23 AM
albanks albanks is offline
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thanks guys. I finally have a few minutes today. I think I'm going to get back in there for a bit today and take care of a few things. appreciate the advice.
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  #62  
Old 05-18-2018, 05:54 PM
albanks albanks is offline
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Quick ?

I get programming to my sets via the following chain:

Dvd player-macrovision remover thing-rf modulator-coaxial converter.

So the signal makes a long, strange trip.

In short, the set runs great, but the audio is full of hum/noise/interference whatever you want to call it.

Is there a remedy for this or is it par for the course given the set up?

Thanks in advance
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  #63  
Old 05-18-2018, 07:09 PM
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If the picture is OK, no reason why the audio should be bad with your setup. Have you tried another TV?
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  #64  
Old 05-19-2018, 10:28 AM
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The exact set and modulator can have an effect on audio quality. If the modulator is one of those consumer-grade models some of those modulate the video over %100 (which generates PM/FM noise based on video content) and later FM modulate the same carrier (adding sound to the noise)...

Some sets like Zeniths had a Buzz control that needed to be set correctly or the sound would be poor.

Knowing the exact type of noise in the audio and more specifics would help in diagnosis.
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  #65  
Old 05-19-2018, 02:19 PM
albanks albanks is offline
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The modulators I have are from best buy and radio shack. The noise is just a background, persistent buzz. It is reduced when I switch to channel 4 on the set and modulator. The noise level varies based on what is shown on screen. DVD menus with or w/o music tend to produce the loudest noise. Once the show gets going the noise/buzz is more steady but can vary based on dialogue/music/silence on screen. I notice the noise varies when I manipulate the connection (anything to do with silver w/ gold plating on the video cables?). Anyway, it's an annoying problem. No other sets to try it on.
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  #66  
Old 05-19-2018, 05:06 PM
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The best thing to do with an intermittent cable is to trash it. You will spend much more $$ worth of your time trying to find out exactly what is wrong with it than buying a new one, and then most likely have to trash it anyway. Do this first before trying any other fixes.

Beyond that, read Electronic M's comments on modulators and also the buzz control that some sets have.
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  #67  
Old 05-19-2018, 06:55 PM
albanks albanks is offline
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Thanks guys.

Pulled up the Sam's for my set. Located buzz control. Looks like I will have to take back of set off again. Doesn't say how to adjust. Turn it clockwise or counter clockwise?

Upon further research I see "buzz" in rf modulator is a big issue. No definitive solution.

Will fiddle w/ buzz thing-a-ma-jig tomorrow.
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  #68  
Old 05-19-2018, 07:25 PM
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Turn the buzz control back and forth until you find the minimum buzz setting.
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  #69  
Old 05-19-2018, 07:30 PM
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Quote:
Originally Posted by old_tv_nut View Post
Turn the buzz control back and forth until you find the minimum buzz setting.
+1

Also regarding modulators, get a Blonder Tongue AM40, AM60 (if you want to transmit wirelessly), or BAVMz (get one that is set to a channel you want that is unused by local DTV) those are professional (cable co grade) equipment with manual modulation control provisions and will allow you to set them to NOT send buzz. They may need a few new lytics but are excellent after that when set up properly.
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  #70  
Old 05-20-2018, 08:23 AM
zeno zeno is offline
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Zeniths one fault in the tube days was audio buzz. Some
sets you just couldnt tame completely. One last thing to
check is be sure the AGC is not set too high. The detector coil
could be touched up also but its best to leave that be.

73 Zeno
LFOD !
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  #71  
Old 05-20-2018, 03:11 PM
albanks albanks is offline
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Thanks everyone. Adjusted Buzz control. Marginal to decent improvement. At this point, ANY improvement is a win.

Zeno, you're breaking my heart. Just put the back on for the 32nd time in three days. I saw the ACG before I put it back on the last time, asked myself, "Gee, wonder what that does?"

If this is worth adjusting I would open it back up. What do I do, just turn it left/right while observing picture/sound?

Thanks again everyone, this site is so helpful (especially to someone just getting started).
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  #72  
Old 05-20-2018, 06:34 PM
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AGC will have a particular adjustment routine in the service manual.

Generally, setting too low causes low contrast weak picture and even loss of sync, while setting it too high can cause overload and loss of sync (picture breakup). It may be possible to set it high for super contrast without breakup, but then have the picture break up when you change channels.

For my RCA CTC-5, they tell you to adjust upward until breakup, then back off to get a picture, then switch to a blank channel and back; if it breaks up again, reduce the setting some more.

The laboratory procedure for any set would be to adjust for a specified known video detector output level with a scope on a test pattern.

Don't know the recommended procedure for your set, but if you don't have it you can try the breakup-restore procedure. You may very well find that setting it wrong increases the buzz too.
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  #73  
Old 05-22-2018, 06:52 PM
albanks albanks is offline
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Quote:
Originally Posted by old_tv_nut View Post
AGC will have a particular adjustment routine in the service manual.

Generally, setting too low causes low contrast weak picture and even loss of sync, while setting it too high can cause overload and loss of sync (picture breakup). It may be possible to set it high for super contrast without breakup, but then have the picture break up when you change channels.

For my RCA CTC-5, they tell you to adjust upward until breakup, then back off to get a picture, then switch to a blank channel and back; if it breaks up again, reduce the setting some more.

The laboratory procedure for any set would be to adjust for a specified known video detector output level with a scope on a test pattern.

Don't know the recommended procedure for your set, but if you don't have it you can try the breakup-restore procedure. You may very well find that setting it wrong increases the buzz too.
Thank you. I will be getting back in there soon. Will check that out!
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  #74  
Old 05-26-2018, 12:44 PM
albanks albanks is offline
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Another day, another problem.

So this set has been working so great, on for about 30 hours without any problem whatsoever.

A couple of days ago I was faced with a novel problem. The power and volume knob popped off and the plastic lever was seemingly too short to get it back on. Anyway, I did get that back on, unfortunately with the aid of super glue. I did have to pull the plastic lever out a bit too.

While I had it opened up I said let me fool with the ACG so that this could be hopefully the LAST time I have to open it up (at least for a while).

I am not sure what happened but I set it up in a place so I could fool with the buzz control and ACG. Then, it suddenly would not turn on. I mean it turns on, all the tubes light up w/ the exception of the HV rectifier tube. No raster.

Any ideas? Did I short something out? Did it have to do with the fiddling of the on/off switch? Fuse?

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  #75  
Old 05-26-2018, 07:18 PM
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If the tubes are lighting but no sound or other signs of life then you lost B+... Probably the main rail off off the rectifier. Figure out where it is dead with voltage checks.
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