48 line 64 line Conversion

[Harry Dalek]

Harry, R702 (and it's conterpart R724) are there to limit the discharge current through the discharge transistor, they should have no effect on timing at all.

The only components involved with timing and ramp amplitude are R704/R724 and C706/C726. That's it. Nothing else.

I'm still vague about the frame and line sync of these other modes apart from the NBTVA 32-line standard. If you could post up the files you're using I'll have a look at them, the format may not be suitable for what you've built so far.

Steve A.

Hi Steve

Yes i understand those don't effect the timing ....Klass mentioned R702 adjusting it lower might stop the fly back line being visible that's what i was adjusting to day i found i didn't get a result of that so i looked into changing the value of R701 to a higher resistance in case the pulse going to it was to high for 60 line for some reason .
It did stop the fly back line being visible but i found removing the pulse to 6E altogether same result and its still rolling back into framing i don't understand why but it does .
The videos i have posted on page 1 first page half way down here Steve i am using mainly dom64 48 ... some times gary 60 line but all Doms video software to make the wav video files seem to work better on this monitor...
I would use a standard known correct format but i can only use what is about to make the higher line rates i am interested what you think looking at them .

[Harry Dalek]

Indeed, the 39 ohm limits the discharge current of the capacitor and defines the fly back time. As I have seen in the 60 lines images fly back takes 2 lines, so you miss 2 lines of video (the first one was launched sky high). And yes, if you have 60 lines, who cares about 2 missing lines, but if they are in the video you want to see them.

Well Klass if the video is in sync one or two lines missing not to much of a problem for me .
The last you tube video was 64 line i have no adjustment workable at the moment to that sky high line i can even the first and last line in 32 line works fine here as Steve designed it with the course and fine tuning framing controls in 32 line those even out ...
Here on 64 its stuck like that high line the framing tuning controls i see no control effect on it adjusting them so some thing is off wack there at the higher rates .
Its no ones fault or any thing its just changing things here as i and you and Steve see them and its the problems you have trying something new .

So fly back should be as short as possible. Now you can see them you can experiment with them and after they are short enough you may suppress the remains.

Its sort of a catch 22 Klass as the circuit i am using is Steve's and partly yours too and i would rather get advice on the change than me stuffing around to much ....what ever i do i just experiment in other part values to see if i can see a result but me changing the circuits i know would not be wise .

[Harry Dalek]

Ok heres the software i am using .
Doms computer screen grabs to make the video
Gary's either a video file cam or gif to make a video file