CTC5 Video Response

[ceebee23]

This is ironic because in Europe, early colour sets actually resolved only about this number of lines. One of the, reported, reasons the BBC did not want to go forward with 405 line NTSC colour was that side by side 625 and 405 line colour on the sets of the day would have barely appeared different and would have made a change to 625 line harder to sell to the government and public.

[Penthode]

The BBC moving forward with 625 lines was to fall in line with most of the rest of Europe. 405 line had a Kell factor of 1 whereas 625 had a Kell factor of about 0.7, if I recall correctly. (525 line Kell facor is 0.6 which is why 525 line pictures often appear to have less resolution).

Interestingly, France switched from 819 lines to 625 lines but transmitted positive modulation with AM sound. And then, to top it off, SECAM color modulation. But at least standards conversion for Euro video exchange would be a lot simpler.

Back to the CTC5: I am going to perform a video amplifier sweep to get to the bottom of the picture quality issue. I am suspicious of the encapsulated peaking coils and also of the delay line and/or its termination.

I would like to know if other CTC5 owners have ever seen a "crisp" picture on these sets?