View Single Post
  #35  
Old 10-06-2013, 03:20 PM
Penthode's Avatar
Penthode Penthode is offline
VideoKarma Member
 
Join Date: Jun 2009
Location: Kitchener/Waterloo Ontario Canada
Posts: 1,059
Interesting about the interlacing. The earlier black and white sets especially from the more expensive RCAs (630TS through 9TC270) had more complicated sync amplification and two sync clippers. Along with the good, more comprehensive vertical sync integration and the standard blocking oscillator, the interlace is generally excellent over a wider range of the vertical hold control. The cleaness of the vertical sync applied to the vertical oscilator is demonstrated when you intentionally roll the picture with the vertcal hold ids a "smooth" roll rather than a "jerky" roll which implies fully stripped sync free from any remaining video.

The mid 50's RCA sets had considerably cheapened sync circuits and disposal of the blocking oscillator transformer with feedback from the output stage expands the problem of oscilator drift from one to two stages. (I however thought the 'CT55 was the last color set to maintain the transformer). Maintaining good interlace would be affected.

It suggests to me that the designers in the mid '50's were on a tight budget to remain competitive. I'd be curious of others thoughts and if others have had the same problem with mid 50's RCA vertcal circuits. (I am currently tracing a vertical sync drift in my CTC5 as the set warms up over 1/2 hour).
Reply With Quote
Audiokarma