Pc engine duo rgb problem

[nevarna]

I have wired up my pc engine for rgb made a rgb scart cable, i also have an external power supply sending 12v to pin 16 (blanking signal) for my sony monitor to switch to rgb. when i switch to rgb the picture jumps quite abit do i need 100ohm resistor on pin 8 (5v line) will 100ohms drop this to 3 v ?

[Midori]

It is probably because you have an external power adaptor för the blanking signal. Good idea, however the reality is evil and harsh :-) The ground signals from your PCE and the external power adaptor will conflict and the result is your jumpy image(someone else can surely explain this in a better fashion).

If you want 12V you should instead use the same adaptor that powers your PCE. Pick the 12 signal inside the console before it is converted to 5V by the regulators. That should do the trick :-) And use a more powerful resistor, use a 560 ohm one instead. It'll probably work with 100 ohm but it is better to take 560 ohms.

[nevarna]

ill see if i can give that a try.
I also get an unstable picture on another rgb enabled tv i have that is lcd this is running without the 12v on pin 16 and just a 100ohms resistor between pin 8 and pin 16. its running in rgb mode but the top of the screen is unstable. most people put it down to the voltage no being lowered enough on pin 8.
is this right ?