exxos's Atari, Amiga & retro forum

sandord wrote: 19 Oct 2018 11:28 What was it? 😉

No 12V so TV didn't auto switch to scart :roll: :lol:

Now we just need a pic of your favourite game :)

Awesome.For.Sure :)

Icky wrote: 19 Oct 2018 12:01 Now we just need a pic of your favourite game :)

Thing is, I can't see any of the cars. Its like the whole screen is like 50% darker than it should be. So I need to work out whats gone wrong there. Probably slight bias issue on the RGB drivers :roll:

Looking good to me still. Well done.

exxos wrote: 19 Oct 2018 13:09 Thing is, I can't see any of the cars. Its like the whole screen is like 50% darker than it should be. So I need to work out whats gone wrong there. Probably slight bias issue on the RGB drivers :roll:

Great game. Always makes me chuckle seeing your pink monitor :) - My daughter used to have one just like that.

This may be why I ended up reducing the RGB resistor values when sorting out my monitor cable.

Icky wrote: 19 Oct 2018 13:27 This may be why I ended up reducing the RGB resistor values when sorting out my monitor cable.

I took out the 3 diodes in the RGB lines, (ups the voltage).. now I have a proper image, but now to bright! :lol:


So diodes technically not needed :P

In light of what I said in the other thread, ultimately if we ran this offer regulator, it would help a little bit of interference on the drivers, and we could also put a preset to adjust the voltage, this way people could just set it to whatever brightness they wanted..

There will also, maybe just easier to go with the Falcon DAC instead..

My wife sees that TV she would have to have one!

I've been looking at the odd dot crawl/ interference on the video..

I added in some 50pF caps, on the RGB and H&Vsync lines, and the problem is indeed a lot less now.

I also noticed after doing the other brightness fix, that the horizontal interference on the desktop drag bar seems to be back again :(


I have looked into this noise before, on a normal STFM as mentioned before elsewhere. But I think the problem is here that the slightest bit of noise on the RGB lines or power rail is actually been amplified by the RGB drivers.

On the Falcon, I never saw any of this interference, some hoping this is because of the Video DAC used. As mentioned, I have designed the board to use this chip, so it is strongly looking like that is the direction I will go in.

Going to try some caps on the RGB transistor bases next, to see what that does...

EDIT:

Did not fix the noise on the drag bar, interference was almost gone on the background green, but also it blurred the image a lot as well.. Not really surprised.