Before the loss of the perfectly fine analog TV signal my set worked fine. Now that I have to use a converter for the digital channels the sound is low for one thing and doesn't tune to the best picture. Another device like a VCR is better, but not much better. I haven't tried a DVD yet, but that's not the issue.

Channels 3 and 4 were never used around here, but now they are the only two choices. It is obliviously a matter of alignment which many of us are smart enough to stay away from. I am hoping that someone who does understand this condition and/or is familiar with these sets (one piece chassis) can point me to the right place to perhaps touch this up. It can't be off by much, so I assume that there is a coil somewhere that I can carefully adjust to bring the best sound over the best picture.

I have similar problems with all of my vintage sets when I use the converters. I have three, so it's not the box. Thanks folks!

I'd try a Blonder Tongue Agile Modulator. Most consumer grade RF modulators fall far short of broadcast standards.

Before the loss of the perfectly fine analog TV signal my set worked fine. Now that I have to use a converter for the digital channels the sound is low for one thing and doesn't tune to the best picture. Another device like a VCR is better, but not much better. I haven't tried a DVD yet, but that's not the issue.

Channels 3 and 4 were never used around here, but now they are the only two choices. It is obliviously a matter of alignment which many of us are smart enough to stay away from. I am hoping that someone who does understand this condition and/or is familiar with these sets (one piece chassis) can point me to the right place to perhaps touch this up. It can't be off by much, so I assume that there is a coil somewhere that I can carefully adjust to bring the best sound over the best picture.

I have similar problems with all of my vintage sets when I use the converters. I have three, so it's not the box. Thanks folks!
What make of converter are you using?
Magnavox is one, that doesn't seem to work very well, on certain sets, even the newer, solid state sets. I generally use the audio-video outputs on them.
A strong possibility is the oscillator slug on the Philco set might need readjusting. It depends how well the fine tuning works. :scratch2:

I run into the same issue on some sets. Some sets I can get tuned on frequency, but I can't seem to lose an audio hum with the converter. Agile modulator works fine on them though.

If "agile modulator" is a new concept for you, this article describes how I use one to broadcast TV throughout my house:

http://antiqueradio.org/HomeTVTransmitter.htm

Phil Nelson
Phil's Old Rados
http://antiqueradio.org/index.html

Broadcast analog signals had a stronger audio carrier relative to the video carrier [as high as -7 dB] than the channel 3/4 modulators used in VCRs, DVDs, or digital converter boxes. This is because these simple modulators first frequency modulated a 4.5 MHz audio intercarrier and added it to the baseband video before modulating on the channel 3 or 4 carrier. Lower level [typically -15 dB] prevents generation of chroma/sound beats, but makes the alignment of old sets more critical.

Professional agile modulators may have adjustable audio carrier level and be capable of the higher ratios.

I have a Zenith converter and it seems to work on the older retro B&W sets, but it does seem to produce a fine beat effect in the picture that sort of looks like a herringbone pattern - sort of like a screen effect. Looks like 4.5 Mhz beat, but tuning the 4.5 trap doesn't help it. It shows up on all the old B&W consoles and my RCA TS721 as well, however it isn't there on my RCA color CTC9. I wonder if it has to do with the 3.58 color burst signal.

If it is strongest on saturated primary colors and looks sort of like a checker board when viewed up close then you are seeing the 3.58Mhz color subcarrier.

If it is strongest on saturated primary colors and looks sort of like a checker board when viewed up close then you are seeing the 3.58Mhz color subcarrier.

Correct - it should disappear if you are looking at monochrome material.

What make of converter are you using?
Magnavox is one, that doesn't seem to work very well, on certain sets, even the newer, solid state sets. I generally use the audio-video outputs on them.
A strong possibility is the oscillator slug on the Philco set might need readjusting. It depends how well the fine tuning works. :scratch2:

I have two converters. One is a Magnavox TB100MW9, and the other is a Digital Stream DTX 9950. The Stream is superior for a few reasons, but both do fine on solid state stuff. Now, I think you hit the nail on the head with the oscillator slug needing readjustment. The fine tuning works fine. I am hoping someone familiar with this chassis will direct me to the right slug. I don't want to mess the set up.

NOW, here is something interesting. Tonight I took the Digital Stream and hooked it to my 49ish RCA TC-127 which has had low volume issues since I restored it. I wasn't even getting decent video and almost no audio, so I started playing with the coaxial cable. I found that if I only touched the center conductor to the connector without letting the outer shell touch (which is hard) that I ended up with almost perfect video and audio. I believe I will disconnect one side of the RF adapter at the antenna terminal and let it ride. Very happy with that discovery, but I don't understand it.

Thanks everyone for the ideas. I am not familiar with "Blonde Tongue" or "Agile" converters.

The pre-1950 RCA sets had a very very strange RF setup.
You should try using a standard 75 to 300 ohm balun, the cheap
ones from Radio Shack, and connect one side of the 300 ohm line output to
chassis ground and the other side to one of the RF terminals ...
try both, they are not equivalent. Note that this may require fairly long leads ...
this is immaterial on channels 3 or 4.

My such set (a 9T-246) has a plug-in
thing for the antenna lead which is supposed to support 75 Ohms
directly with a different plug, and that simply does not work.

Doug McDonald

Now, I think you hit the nail on the head with the oscillator slug needing readjustment. The fine tuning works fine. I am hoping someone familiar with this chassis will direct me to the right slug. I don't want to mess the set up.I don't have a service manual for your TV, but on many sets the oscillator adjuster is inside a little hole on the front of the tuner, something like this diagram (labeled A14).

http://antiqueradio.org/art/Admiral24C15OscillatorAdjustment.jpg

When you turn to a given channel, its adjuster appears through that little hole (labeled H). In your TV, everything would have different labels, of course. First, tune the TV into a signal and set the fine tuner to the middle of its range. Then, using a very thin, non-metallic screwdriver, you turn the adjuster until you have the best picture. Sometimes the adjuster is deep inside that hole, so it helps to use a strong flashlight.

Be careful not to screw the adjuster out too far. On some TVs, the screw will fall out and perhaps get stuck in an inaccessible place.

It's not clear to me that this is the root of your problem, but if you are careful, tweaking the oscillators for channels 3 and 4 can't hurt. If you can already use the fine tuner throughout its range to tune the signal completely in and out in both directions, then adjusting the oscillator won't improve anything. It is just a way to get the tuner (and fine tuner) centered on the correct frequency, if that makes any sense.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

the adjustment for channel 3 or 4 tweaked in the front of the tuner should help align it closer

OK Phil and Kramden66, I am familiar with this adjustment, but I lean toward the idea or fact that it would center the range of the fine tuner for that specific selection. My fine tuner is about dead center. My problem is that a good sound signal is just off 'to the side' if you will to the best (or worst) video signal; right on the edge.

I feel badly that I have forgotten just what lays the two in alignment. Thanks Phil for the graphic. That will help a lot of folks and me too as it is similar in nature to my tuner. We're getting there, and as for the RCA I feel that going with the one side to antenna input and the other to ground may be the thing to do.

a good sound signal is just off 'to the side' if you will to the best (or worst) video signal; right on the edge.Sometimes you can fine-tune it for best picture and then carefully tweak the sound alignment adjusters to match, so to speak. Those will be identified in the Sams manual, if you have that.

Phil Nelson

If the sound and picture don't tune at the same point, it should be obvious that it's not the tuner, which has no independent adjustment for the two (unless it has an internal sound trap adjustment, which I doubt). It has to be something in the IF (like the sound trap / sound takeoff) or sound section alignment.

Given the discussion of BT agile modulators here, perhaps this is a relevant thread for me to ask... I see them in bounty on a certain auction site but I don't know what model designations would be appropriate for older tvs that only have channels 2-13. The configurable ones go for significantly more than the single-channel ones, and some seem to have an interchangeable frequency unit, while others are fixed to a particular channel (or class)...

If I'm not hijacking the thread too much, what should one look for, in regards to video for such an older set?

Sometimes you can fine-tune it for best picture and then carefully tweak the sound alignment adjusters to match, so to speak. Those will be identified in the Sams manual, if you have that.Phil Nelson

Actually, for this to be my first set purchase in my life (back about 1982), and now a fixture that is loved in my home; strangely I don't have a Sam's or other schematic. Why? It's never needed service much (one cap and a tube or two).

If anyone has a .pdf or whatnot I would love to have it. For the record and from what I can tell on the sales brochure that I am going to attempt to post, it is a Model 4136 with the 330 chassis.

To OldTVnut, that sound alignment advice is good and well taken, but I must reiterate that there were no issues at all when I had analog signal, but I seem to have this with these other devices that we must use to keep using our sets.

I hope these pics come through!

OK folks; no need for rescue or searching for schematics (although I still wouldn't mind having one), the Philco proves once again to be mighty and in good working order! There should be a Guinness world record for consumer electronics logetivity! 57 YEARS!?!?!

Anyway, I took the one antenna terminal idea (and converter) to the Philco and tried various configurations. The one that works best is to simply leave one side of the coaxial adapter off. I did that and my sound would sync with the video. The picture still had a little snow (yes snow) in its digital display, so I touched one lead of the built in antenna to the dangling end of the coaxial adapter; better.

Then I touched the other side of the built in job and BAM, no snow with synced audio and video AND good volume level which I was battling with both sets! The only problem left was a faint wave oscillating across the screen. Still acceptable, but could be much better. I flipped the channels 3 and 4 selector on the digital converter to channel 4 and tuned the set to 4 and it all went away. I am pleasantly pleased to say the least.

I know someone will deduce that my whole problem was the simple move to another channel, but that's not the case. I had tried every possible configuration before I discovered this thing of leaving one side of the antenna input disconnected. As well when I had both leads connected and was coming up with the original problem and topic I had noticed that touching the built in antenna to the terminals improved the situation, but did not correct it.

Imagine the repair work attempts and hours of frustration that I would have gone through if I had blamed this on both sets as opposed to the peripherals! Live and learn, but it's fun when you get it the easy way..

Thanks to all for the input and ideas, and I hope that this will help others with similar problems with their vintage sets compatibility to modern equipment.