If the RF from the VCR is strong you could be picking up a harmonic also. My Sylvania does that when I have a modulator cranked up to a high level. Usually if the RF is that strong the AGC has trouble handling it too.

John

Went to Target and bought a Memorex DVD player and a GE RF Modulator.
All for $47, not too bad..I will be hooking them up tonite to see if I can get a better picture.
Thanks again!

Two comments:

1) Bear in mind that there is often skew in modern equpment of the horizontal sync at the vertical sync. This causes a bend at the top of the picture frame. My old Zenith roundie used to do that, and I had to change out some capacitors in the horizontal phase cktry in the phase det section--IIRC. Such corrected the problem--and added a bit more jitter on weak, snowy signals. Trade-off was accepted by me at the time.

2) This one can bop you upside the head from left field, as you have your attention on a video or raster problem, and the problem is not in any of that cktry. On some of the older monochrome sets of the 1950s some manufacturers engaged the sound output tube in the dual application of voltage regulator for such sections in the set that required 130V or lower for B+. It varied from one model or brand to the next as to what sections were supplied off the cathode of that tube, and a clapped-out sound output tube may provide adequate audio, but still be too weak to provide off its cathode adequate supply to whatever other sections of the chassis.

R&R sound output if in doubt. Just my twopence...

Checked the V17 section and it is the correct .005uF cap.
Spent the night tweeking again.
Hooked up the DVD and GE modulator..horrible snowy picture and no sound.
Did everything and turned evy knob and no good results.
Went back to the VCR but kept loosing the picture.
Tried running it through the modulator too..nothing.
Boy this is hard tediuos work..you gotta love this..definetly some pain involved.
Well finally turned the front tuner knobs to this small spot on the dial where I got sound.:banana:
But it is just out of contrast for a good picture. :tears:
So I get an okay picture...no sound.:thumbsdn:
Then I get okay sound and not so good of a picture.:thumbsdn:
Going back to Target and exchange for another type of RF modulator from a different manufacturer.:D
What do you guys think? and suggestions?

Did you test the DVD and modulator on a modern set? It could be ok.:scratch2:

jr

Did that tuner have any paper/wax caps in it? Sometimes those are easily missed if the tuner cover is in place. Most tuners don't have any paper caps in there, and others may have one or two.

Also, using your Sams info, check your resistance readings from tube socket pins to ground & B+. One of my sets had some resistor issues in the tuner that caused weak pic & sound.... bounced right back after finding 3 resistors that needed changing.

It doesn't appear that there are any paper capacitors in the tuner.

This set is very similar to my 1-108 chassis. Except for the tuner and the last stage of the horizontal section the circuitry is nearly identical. It's a straightforward design without any magic tricks.

Hopefully the problem so far is just with the modulator, but take a look at this attachment. I think it resembles what you're seeing now.

I hope you don't have the exact same problem, because it'll take some delicate work. I suspect though that you have a problem with one of the video IF stages not working and the signal is just bleeding through. This is what caused the image I've attached. A video IF transformer was open and I had to rewind it. The same effect could be caused by a bad tube or resistor.

I believe that the IF transformer had burned up because of the numerous times that the seller, and perhaps the person he got the set from, had powered it up hoping to have it work. A shorted paper cap probably burned it up.

I'd point you to my thread, but all the attachments aren't displaying since the move to VK.

Grrrr. VK is too smart for it's own good. Even after renaming the image it wouldn't let me upload it saying that I've already used it before. I had to change it to a different file type.

John

When I first plugged in the DVD player and the modulator, I got a full picture on the screen. It was snowy and not clear. not really distorted just a crappy picture.

With the VCR playing a tape throught the 300ohm to 75ohm connector...I twiddled with all of the adjustments trying to get the best picture..most of the time just making it worse. But I never got two images like in your picture. I did however get the two picture one on top of eachother and I could ot pull the horizontal line down to fill the screen with one picture. Some times I could find a got picture on the sceen with a horizontal line in it..could not get rid of that either.
So I am back to the last post with a decent flagging picture from my VCR... and the sound is just a tweek of the knob to the right on the channel selctor..which then comes in with sound making my picture come out. haha
Did that make any sense from a beginner?
Maybe I should just stick to radios..they seemed a little easier..not that I didnt ask as many questions for radios..but the outcome was better.
But this is fun and interesting and I like a challenge..I just hope you all stick it out with me. (?)
back to the store for a differennt type of RF modulator.
Talk to you soon..with more info and questions..same bat time ..same bat channel.

There aren't two pictures in my photo. That is the horizontal being shifted in phase. The horizontal control tube in my set was leaky causing that, which was a seperate issue. The bad IF section was the cause of the snowy image with what appears to be flagging.

Just imagine my photo with the center part shifted over to the left where it should be.

Don't give up. You are really close. I think you have a single problem at this point which should be easily fixed. Especially if you feel comfortable making some voltage measurements with the set operating.

John

Bought a Philips modulator and hooked it up and I obtained a pretty decent picture:banana:
Just a little..ghosting some times in the left of the screen..but it is not always there.
Now the volume control knob is very crunchy and crackles when turned..sometimes creating enough static to make the picture go out..and I( give the horiz. size control switch a turn back and forth and the picture retuns. I turned the volume control to full and because the sync between good picture and good sound is not dead on..the turner makes the sound quiet and I can listen to show. But as time passes like 15 minutes or so the sound is totally lost.
Shut it off for about 20 minutes and I can get it back again.

So I am really pumped for I can now get a pretty nice picture..really good with no chance of volume. Turn the picture control knob and just barely find a volume signal.
Do you think it could be a particular weak tube that would do this? Which ones should I have tested?

Here are a few shots of the tv with the halolight on lowest setting.
Not sure if I actually like watching the tv with it on..but it is cool!

I think mine does the exact same thing! How weird! The sound slowly fades out over 15-20 minutes. I never went back in there to look for that problem. Figured I missed something. Probably a resistor drifting somewhere. I had spent a lot of time on that set and got kinda tired of it for a while. Always figured I'd get back in there another day to find that issue.

Do you think it (sound quality and fade) could be due to a particular tube on the chassis?
Which ones would you pull and check?
I will have to bring the tubes to an old tv store in town...
Also any comments on the ghosting that sometimes shows up in the left of the screen?

Not that tubes wouldn't cause the sound fade, but I believe it would be more likely a resistor or capacitor changing value as the chassis warms. Since you've gotten rid of all your paper/wax caps, I would do some resistance checks from the tube sockets using your info in the sams. Keep in mind, you would want to do these checks pretty quick after powering down the set since the issue seems to be heat related.

Let's say you find a resistance reading to be way off from what it should be on a certain tube socket... wait a few minutes and come back to check it again. If the same check comes back a second time as something closer to what it's supposed to be, there's a pretty good chance you've found the problem.

If you think the only thing changing for you is your sound going away, first check thru all the sound circuits for resistance readings... starting with the sound output stage and work backwards back to the sound IF.

It can be quite surprising just how many resistors you might find way out of spec. If a particular tube socket pin is supposed to show 500 ohms from that pin to ground (or back to the B+ source) and your getting 250k ohms, that means that a resistor or several in that particular path have changed value. YOu would then follow your schematic from that socket pin backwards and check the resistors in that path... likely to find that bad one... or more.

You must also keep in mind that some of these paths can have slightly varied readings because a certain control adjustment (such as contrast, vert hold, or any other pot) will have an affect on your reading as it may be part of the circuit you're checking.

If the sound problem was a tube, it could be anything from the speaker backwards.

Regarding the ghosts, bad tubes in the IF strip commonly cause this... gassy or shorted. My CM color set used to have some serious ghosting until I found one of the IF tubes to have a short. Getting an IF alignment could also correct your problem... but that's something best left to those who know how to do it and should only be done once you've tried everything else. You don't want to go in there turning things... would just make it worse.

The most probable resistors to go bad in the audio section are R118 a 470ohm 1 watt resistor and R115 a 270 ohm 1 watt resistor. R118 is operated at about 0.8 watts, very close to its rating and lives a hard life.

I had a problem with heater to cathode leakage in my 6Y6 output stage. You have a 6V6, but it's very similar. The leakage did cause some audio fade and crackling. Unfortunately most tube testers aren't sensitive enough to find small leaks that can cause a problem.

The heater is biased at -135 volts, about 15 volts below the nominal -120 volts the cathode operates at.

John

Went to the old tv tube store in the next town and had them test some tubes.
Both the 6AU6's had a short and were no good.
The 6V6GT was nothing to brag about but would work.
And the 6T8 was week..I gues these had about 4 sections inside them and were known to be very noisey.
So I will need to wait til monday to get the other 6AU6 to give it another test run.
Guess TV night will have to be in color this weekend...bumber.
Just another quick question what does the knob/adjuster on the HV section do?