Rca 730tv1

[vts1134]

Back under my 730TV1 this past weekend.



I had a problem with the horizontal on the set. As the set would warm up the horizontal would drift which would require an adjustment of the horizontal hold. Eventually, 1 to 1 1/2 hours of use, I would run out of room on the hold control and the picture would fall out of sync. This is our only TV in the upstairs living room and on the weekends we definitely need more than an hour's worth of viewing time, and it's a pain to have to adjust the controls every 15 to 20 minutes.

I replaced a very out of spec resistor in the horizontal oscillator circuit, but after repeating the horizontal alignment procedure it again drifted after 45 minutes or so. I then (and I can't believe I didn't start here) swapped the horizontal oscillator 6SN7 tube with another one in the set. I fired the set up without doing the alignment procedure and let it play. It was rock solid with no drifting in the horizontal for an hour or so. I had to turn it off at that point as I was ready to head to bed. I'll fire the set up again tonight and see if it makes it past the two hour mark without the need to adjust the horizontal control.