i connected pin 6 to 20 and then pin 4 to 16. it worked with one small problem; the (panasonic) tv would occasionally 'detect' again that its rgb (and not composite) and it would display 'RGB' in corner for a sec.
probably because there's not enough voltage on SCARTpin16? it was a bit annoying, so I connected +5V to 220ohms and then scart pin 16 (I left CPC pin 4 unconnected) and it works better.
if I understood correctly we can connect either pin 4 (SYNC) or pin 6 (LUM) from CPC to pin 20 on SCART? but what about SCART pin16, is there a way to make it work without the need for +5V? (would it perhaps work with 6->16 ?)
Quote from: orange on 09:13, 28 April 10
i connected pin 6 to 20 and then pin 4 to 16. it worked with one small problem; the (panasonic) tv would occasionally 'detect' again that its rgb (and not composite) and it would display 'RGB' in corner for a sec.
probably because there's not enough voltage on SCARTpin16? it was a bit annoying, so I connected +5V to 220ohms and then scart pin 16 (I left CPC pin 4 unconnected) and it works better.
if I understood correctly we can connect either pin 4 (SYNC) or pin 6 (LUM) from CPC to pin 20 on SCART? but what about SCART pin16, is there a way to make it work without the need for +5V? (would it perhaps work with 6->16 ?)
LUM is only required for green monitor.
What are you doing exactly?
Did you see http://cpcwiki.eu/index.php/TV_SCART_cable ?
Are you using the same connection, but still get problems?
Of course, the batteries in above schematics aren't that optimal. Using a resistor to 5V to produce 1V-3V would be better than batteries. But it with different TVs you may need different resistors. Maybe best would be using two 1K Ohm resistors:
GND ------1K-------x------1K------5V
In the middle (x) you should get perfect 2.5V. And even if the TV drags it down a little, you should still be in the 1V-3V range. Btw. you don't have a multimeter to verify what voltage you have, or do you?
Have you tried the battery-less alternative pinout shown here: http://www.cpcwiki.eu/index.php/TV_SCART_cable
that works on most modern TVs.
Bryce.
Quote from: Bryce on 10:44, 28 April 10that works on most modern TVs.
I have 2 LCD TVs here. For one it works perfectly fine, the other now shows a perfect colour image but at the same time a grey scale ghost image, a few centimetres shifted to the right. That's probably due to the luminance being fed into pin20 I guess. Would there be another option like feeding sync into 20 and luminance into 16 with that capacitor or would that not work?
I haven't tried, give it a go?
Bryce.
Quote from: Bryce on 11:27, 12 February 22
I haven't tried, give it a go?
Bryce.
OK, so nothing obvious that could do any harm, right? then I will try and let you know.
No, my guess is that you will get a flickering picture as if the sync signal was too low.
Bryce.
Quote from: Bryce on 11:54, 12 February 22No, my guess is that you will get a flickering picture as if the sync signal was too low.
no flickering, but it also doesn't switch to RGB automatically.
btw: I only had a 10V capacitor. Will that be sufficient? In the original thread you mentioned 16V but on the Wiki page it only says 100µf but nothing about the voltage.
10V is fine. I wrote 16V because that's usually the standard value you find most often.
Bryce.
Quote from: Bryce on 09:33, 14 February 22Bryce.
So, I do now have a second LCD with a greyscale ghost image. Seems this could be a pattern for cheap, small "camping" LCD TVs. Would it make sense to add a note to the WIKI article, that this can happen with the battery-less alternative?