I need to do my first alignment. I have an early 60's 19" B&W tabletop TV, model G2112J, Chassis 16G27T. I replaced all the electrolytic and paper caps, the set seems really stable, I'll replace any out of range resistors next. But the alignment seems off to me, in that I cannot get the image and the sound to be optimal at the same time. Rotating the fine tuning makes on eor the other work well. Would I be messing with slugs in the tuner or in the if chain to correct this. Also, I do not have an oscilloscope.

please advise.

You can't do a proper alignment without a scope, you need to see the response curve. That said, it might still be possible to get audio in line without special gear. What you do is get the picture tuned in nicely, then fool around with the audio IF transformer to see if audio can be pulled in. If not, you'll have no choice but to fix the error in the video IF response because the 4.5mhz audio has moved.

I just aligned a color set that it appears someone peaked the IF for maximum sensitivity using a weak station. What a screwed up mess that was!!
Dont even attempt it without the propper equiptment and test leads.

You can mess with the stuff after the audio detector and the sams should give directions for that without test equiptment. Dont mess with the rest.

Could be a leaky detector diode rather than alignment

Although it's far less straightforward than using the proper equipment, sound IF can sometimes be aligned by ear.

Video alignment without equipment is really asking for trouble. In the case described above, it's easy to see what went wrong. Unlike a radio, a video IF is absolutely NOT intended to be aligned for maximum sensitivity. It is designed to be aligned for uniform sensitivity over a fairly broad range of frequencies. That means that the different IF slugs actually end up getting peaked at different frequencies. Almost impossible to get right by eye (although I have a hunch I could do it if I had a good reason to...).

Back to the sound IF: Since your set is "modern," it has intercarrier sound IF. For the most part, if sound and picture don't come in at the same time, it's because the video IF passband is all screwed up (not managing to let both the sound carrier and picture carrier through at the same time, which is necessary).

You could try seeing whether tuning up the audio IF alone will help. Since it's an intercarrier set, you don't need a signal generator. Any station will definitely give you a 4.5 MHz sound IF signal to work with. Turn the fine tuning into a range where the sound is not touchy (not near the edge of where sound is coming in). Peak all the sound IF transformers for maximum signal strength (using a very weak station, or very weakly coupled DTV converter or cable signal), except for the secondary of the final sound IF transformer (the demodulator secondary). That one should be tuned for best sound quality (least distortion) and least video noise (like 60 Hz buzz). Most likely the two effects will coincide.

Once you've done this, if you go back and tune for good picture and don't get sound, the problem is in the video IF. Best to buy a sweep generator and scope for video IF alignment.

By the way, if you had a very early set with split sound/video IF, the whole issue of how to get the audio and video at the same time is handled very differently. While it's much easier to get them back together in such a set, they are also very touchy, drifty, and hard to tune in the first place. Those almost always need sound IF realignment during restoration (and again a year later, and a year after that...). But that's not what you have.

What would be a "good" sweep generator and scope to get? Any suggestions? I'm probably going to try eBay first...

TV IF alignment is tricky business even if you think you have the knack. But don't let that stop you

You can probably get away with tweaking the sound discriminator coil. Depending what you are using for an analog TV source, maybe the problem is there.

DTV converters have generally crappy audio in my opinion or modulators.

You will need a sweep generator that covers the band of frequency of your IF noting earlier non-color sets were down around 20 MHz IF frequency. You need a scope with good LOW frequency (DC) response.

By the end of the 1950's TV sets used what is called inter-carrier sound. Analog TV audio is actually an FM carrier transmitted on a frequency 4.5 MHz higher than the visual carrier. It is picked off at the video detector and usually gets one stage of audio IF before the audio discriminator.

You could inject a 4.5 MHz signal if you had one iof those B&K 1077 type units.

I tried a bunch of sweep generators and marker generators and scopes to get a decent alignment setup and then picked my first victum which was a Tele-Tone 7 inch electrostatic, which I did finally get aligned and working quite well.

Jim

If your only problem is that sound and video don't coincide, I would try aligning the sound, as Tom suggested, before investing in a bunch of equipment.

If you want to learn alignment for fun, anyway, I'd advise getting the newest solid-state equipment that you can afford. Vintage test gear is often cheap, but it will need the same restoration as a vintage radio or TV, and it may be less accurate even when working perfectly.

If you haven't already done so, read the alignment procedure given in the Sams (http://www.samswebsite.com/) manual for your TV. That will give you a better idea whether you want to tackle this procedure.

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

I watched this video on alignment, http://www.youtube.com/watch?v=I1h5zNFv ... re=related So I'm starting to understand the wide bandpass concept. Also, I have the schematic from Sam's with alignment instructions.

if it actually works, would this 20Mhz oscilloscope be what I wanted?

If I find one without a probe, is it worth getting? How common are those probes? Can I construct on myself?

As the guy's say if you want to master the craft of alignment you will need a collection of test equipment. If you just want to fix one TV it may not be worth the trouble.

When you read through the SAM's it always looks simple enough but don't count on the simple part.

I concentrated on old Laboratory test equipment which tends to be quite cheap on the market and is usually more reliable than the TV shop grade.

That said I have a 1950's sweep generator, marker generator and used that with a 1960's Tektronix 547 scope. The old tube type RCA gear is totally reliable and has never had anything done to it since it was made.

To conserve space in my garage/shop I have a Sencore SM-152 sweep generator which I have had to fix and I use that with a HP digital sample scope which I also had to fix (CMOS batteryendectmy). I use the old RCA marker generator (tubes) and verify the frequency with an old but high precision HP counter.

This stuff all cost less than $20 per item.

Then I swear by the B&K 1077's.

All this stuff is cheap on eBay, you just have to accumulate for a year or two.

As far as a scope is concerned, for sweep alignment LOW frequency response is more important the High, because sweep generators use 60 Hz line frequency to sweep across the band you need to see and a DC voltage is applied to the scope to produce the pattern shown in those SAM's instructions.

In the case of a TV, the video detector provides the DC trace for the vertical input on the scope and the horizontal sweep is 60 Hz. A fairly crummy scope can do this.

Actually the biggest problem in buying old lab test equipment is the shipping cost.

Jim