Vintage Sony Trinitron
 

When the first generation Sony 12 inch Trinitrons were introduced in 1969, the model line up was KV 1200U, in basic metal cabinet, 1210U with walnut cabinet and the KV1220U with a fancier walnut cabinet , larger speaker and something called "Sky Tune".

Anybody know what "Sky Tune" did? What differentiated it from the other models? Is it simply AFT?

The blue sky tuning indicator was just a fine tuning aid. IIRC, the blue color band on top of the screen got larger when the fine tuner was set properly.

Smiler to Panasonic's magic line tuning indicator which used a green band in the centre of the screen which when it was tuned properly it would be at it's narrowest.

LOL... I remember that blue expanding band. The first time I encountered one, I thought I had an intermittent shorted CRT!

Charles

That was the same thing I thought, after I installed a brightener on it. The only service information I had on the set was a Tab manual. It had an explaination about it in one of the first chapters. IIRC, it was the only Sony that had a 3AT2 HV rectifier in it.

Thanks guys. I just found a Sony KV 1220U in working condition, should arrive in a few days. I bought an original KV 1210U in 1969, but my wife gave it away to Goodwill in 2006. Been searching for a replacement ever since. :-)

Sure enough, the blue band appears in the upper third of screen. The TV is working great.