10KV caps.

[JohnCT]

Originally Posted by Penthode

I have had 5 decades aligning these early sets with split sound like yours.

And I've got none. Attention being paid!

The distortion cannot be just the ratio detector because the sound IF in a split sound set changes with the fine tuning.

The distortion is gone. Bad cap in the ratio detector and a couple of cranky tubes. Also eardrummed the audio IF. The sound is nice and clear, no buzz, just a tad low in overall volume. Still, it's usable as is.

Remember it isn't an intercarrier sound set where the sound carrier beats with the video carrier to maintain sound over the video tuning range. In a split sound set you adjust for best sound and the picture should and must be set at that point optimally. The sound tunes like an FM radio and when tuned you accept the video as is. This is why you need the proper equipment to do the alignment.

I have several pieces of equipment and, unfortunately, none work at 24mhz that this old girl uses. I've been thinking of modifying my B&K415 (that I bought new). I aligned a few 44mzh TVs back in the 70s with that genny, and it's easy to use and works well.

I also took my VA48, set it to burst sweep, and fed its video output into a B&K1077B analyst (also bought new) and was able to have it convert the VA48 multiburst signal to 24mhz - the 1077 has an infinitely variable IF output.

I don't have the courage to try this hack setup on the Andrea, although I was considering just connecting it to the IF and scoping the video at the detector and see what the multiburst looks like. I may have something else of no value that I can use that frankensetup to experiment with.

I do have a Precision E-200 for which I only have a couple of crystals, but I don't know how accurate a wobbulator setup is.

Seems to me you are almost there and hope to see you cross the finish line.

Thanks. I planned to finish by the fall, and I'm way ahead of the schedule, so I backed off a bit for other projects.

What I really need to find is some sort of matching mahogany base to put it on.

Thanks for the info.

John

[Electronic M]

There's a thread on here where someone found a way to heterodyne the IF of a B&K 415 down to the old 20MHz IF range using a precision oscillator and mixer...it was all external gear that can be easily added and removed from the B&K depending on what IF freq you are aligning in a given day.

[dtvmcdonald]

The problem heterodyning a 41 MHZ sweep generator down to 21
is that to keep the markers correct you need to have the fixed oscillator
at about 20 MHz, which is too close to 21 even with a balanced modulator.

On the other hand you can heterodyne it UP easily to VHS and run it into the tuner ...
if that is aligned broad enough. You can of course check to see that by trying different channels.

O you can just use the markers at their upside down places and get the shape right,
knowing where they actually are.

[Electronic M]

Originally Posted by dtvmcdonald

The problem heterodyning a 41 MHZ sweep generator down to 21
is that to keep the markers correct you need to have the fixed oscillator
at about 20 MHz, which is too close to 21 even with a balanced modulator.

On the other hand you can heterodyne it UP easily to VHS and run it into the tuner ...
if that is aligned broad enough. You can of course check to see that by trying different channels.

O you can just use the markers at their upside down places and get the shape right,
knowing where they actually are.

I forget how exactly they did it but mixing 2 some waves creates new sine waves at both the sum and difference frequencies so they may have used the difference and a higher frequency oscillator or double conversation. ISTR the markers were in the right places...

I may be using my B&K to align a 44MHz set tonight and if that goes well I may dig up that thread and use that to down convert my generator.