Scandoubler Pixel Colour Channel Shifted

Hi There,

Separate to my previous post, I have problem with the output from the scandoubler on my A2000. The red and perhaps blue+green colour channels appear offset with each other. This produces a colourful ghosting effect which is perhaps best described with an image:

I have this effect on two different A2000 motherboards (both Rev 6). What could be the cause of this and how could I solve this?

Many thanks!

  • Amiga model: A2000
  • 680x0 CPU: 68080/68000
  • RAM Configuration: 1 Mb CHIP/128Mb Fast
  • Kickstart, AmigaOS Versions: OS3.1
  • ZZ9000 Firmware version: 1.8
  • ZZ9000 Driver version: N/A (problem observable in early boot menu)
  • Monitor model: Various Samsung monitors
  • Other Zorro cards: None

I probably should have mentioned that I have an R2 board and the fix (drilling the hole at the specified place) has been done and the voltage is correct.

So I spoke to the guys on IRC regarding this problem. It seems like my denise chip needed some different “phase shift”. The user _Bnu was able to produce a firmware that worked with my denise chip and I all colours displaying correctly now…

Hi,
I had this particular issue with SuperDenise, it showed early as boot menu; when replaced with Denise, it showed good picture but more testing with apps like SysInfo show exactly same behaviour like your picture.
Can you share this modified firmware, I’d like to test if it fix my case, too.
Thank you.

I never got a solution for this. A developer contacted me once and offered me a custom firmware which kind of worked but had other issues. To be honest, I got sick of chasing the issue. If after two years of new firmwares the issue hasn’t been fixed, it isn’t going to be fixed.

Thank you for a quick reply !
I understand. It seems that he is no longer active in Amiga development and for Lukas this can’t become a valid support case. Can you share this custom firmware somewhere ? I’m willing to test and take a look at modifications he made, specifically on frequencies he used to tune pixel phase. I might not be getting a solution but at least can try something while I still have some patience. Thnx!

I don’t have this firmware anymore and if I remember correctly, it broke RTG screen modes in strange ways. It was not very useful.

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I see. Thank you anyways.