johnsattuk said:
Thanks for 7000 link, I'll do the Scart mod next, I have some more 1uF caps
I went up the steep learning curve on YPbPr from Dreambox and I find it works perfectly into Panasonic YPbPr component input. There are a few possible pitfalls and some non existent problems. Also there's some wrong and confusing info around web sites.
1. The component signal is put out on the DB scart pins when the video setting is toggled to YPbPr. If you have an RGB connection to your TV, you can check how component is working by tuning to a b/w movie and toggling from RGB to YPbPr. The picture should turn to green and white.
Reason: The transformation is
Y = 0.299R + 0.587G + 0.114B
Pb = 0.492(B-Y) = -0.147R - 0.289G + 0.436B
Pr = 0.877(R-Y) = 0.615R - 0.515G - 0.100B
And for b/w transm, R=G=B, so Y =1 and Pb and Pr both = zero.
On DB,
Y is on scart pin 11 (Y gnd on 9) which is G for RGB
Pb is on scart pin 7 (Pb gnd on 7) which is B for RGB
Pr is on scart pin 15 (Pr gnd on 13) which is R for RGB
So if you send a YPbPr signal to RGB i/p of TV, there is just the lumi signal on G and nothing on the others, hence green picture.
2. To connect to YPbPr phonos on TV from DB scart, a scart to 3 phono cable is needed with the above pin connections. Note, this works both as scart2phono and phono2scart since RGB in and out are on the same scart pins. There may be a scart to component coloured phono leads, but the one I bought (Vivanco) is labelled YCbCr and has R G B coloured phonos. The Cb Cr labels are confusing because that is the notation for digital component which usually has a single multicore cable. Pb Pr is the notation for analogue component via three separate screened leads.
3. It is very important to set the DB to YPbPr while still connected to TV via RBG. If you connect to the YPbPr TV inputs while the cable is still carrying RGB, there is a chance you get a meaningless flashing unstable green picture and you wont be able see the DB menu on screen.
4. If your cable is not marked R G or B, then the way to really find out if your DB is giving out the right signal, is to first tune to a b/w movie with RBG connected. Now toggle to YPbPr. Picture goes green and white. Now disconnect this lead. Plug in scart of scart2phono into DB TV out socket(not VCR out socket!). Switch TV to component i/p. Try each one of the three phono leads in turn into the Y socket. One of them should give a proper b/w picture; the other 2 should give nothing at all. If this is the case, so far so good and you can be reassured that your DB is using the above matrix transformation. If more than one gives a picture (it will be b/w) then there is something wrong with your Db YPbPr output and it's out with the solder station. Otherwise, leave the plug (probably marked G) in the Y socket. Now tune to an appropriate football match. Man U v Chelsea is good and today Boro v Man U was also good. Insert the remaining 2 cables and swap them over until the teams are wearing the right coloured shirts and the grass is green. (Note Boro were in R and Man U, B today.) So Man U are still some use. They more or less swap shirts if the leads are wrong.
Finally, to test the purity, go into the tools menu again and get the video settings up. In the bottom right corner, there is a test button. Press it to get colour bars. The left bar should be a clean untinted white - the acid test. You should also see clean R G B and C M Y (Y this time is yellow which may be a bit muddy.) Press exit to get out of colour bars.
I did this with 7000S, amber screen, bought Oct last year. Perfect results and now I have freed up a RGB scart on my TV for another device.
There is quite a bit of hype about component on the web; some places say it is better for plasmas and projectors than RBG. Because the Pb and Pr are shipped at lower bandwidth (exploiting the eye's deficiencies) it can't possibly be better for short lead connections. But it can be shipped over longer cables with less degradation than RGB so that's its advantage. I have read that it can be shipped over 10s of meters of cat5 cable so useful for sending around a house. But don't set up YPbPr, thinking it will be better than RGB.