A3000 640x512 interlaced mode on PC VGA monitor

Folks,
I've got my A3000 running fine at 640x256 but any interlaced mode is a real colourful mess on either of my PC monitors. No amount of manual monitor tuning seems to help. Am I pushing it trying to get interlaced modes working on a PC monitor or am I missing something?

Running KS 37.175 and WB 38.12. Will KS/WB 3.1 help?

Steve

Re: A3000 640x512 interlaced mode on PC VGA monitor

@SJBUK

There's a little fine tuning pot adjustment near the VGA connector on the back panel which you need to adjust whilst displaying an interlaced mode.

Be gentle, go slowly & listen for a clicking noise as this tells you you have reached one end of the pot & will need to adjust in the opposite direction. It is multiturn & will have a good few rotations from one end to the other.

TC :wink:

Re: A3000 640x512 interlaced mode on PC VGA monitor

Thanks TC. I've tweaked that and managed to get 640x256 nice and stable but any interlace mode is a real mess, not just tearing but severe sync and colour problems. Tried both a Dell and Samsung monitor with exactly the same result.

Re: A3000 640x512 interlaced mode on PC VGA monitor

SJBUK

Are you using a LCD or CRT monitor.

You will find that the "Amber" flicker fixer still outputs at 50Hz in PAL mode which CRTs can cope with LCD's tend to not be able to go below 56-57Hz.

test this by trying an NTSC interlaced mode (60Hz) such as 640x400 If that syncs OK then it's down to the LCD which I've a feeling is what you are using.

These older systems really do function best with CRT's
Even the new Indivision AGA performs much better with a CRT rather than LCD..

Keep us posted

TC :mrgreen:


edit --

Check the link
http://amiga.resource.cx/exp/search.pl? ... 0&company=

You will find a manual & test utility disk here too... The A3000's Amber circuit is based on this card :wink:

Re: A3000 640x512 interlaced mode on PC VGA monitor

They are LCD monitors, no room really for CRT anymore!

Thanks for the link, I'll give it a spin later if I get time and post the results

chiark mentioned it might be a buffer problem and on reflection it does seem similar to problems I've had on faulty PC display cards (dodgy VRAM) in the past.

Cheers,
Steve

Re: A3000 640x512 interlaced mode on PC VGA monitor

@Steve

It's possible there is a fault as the Amber circuit works in 2 entirely different modes depending on whether it is de-interlacing & scandoubling or just scandoubling. The former being the most complex & full use of the circuit & the main reason for the tweaking.

Mate I wish you all the best, the A2320 manual should give you a good understanding of the system function & does have some good troubleshooting tips, it is NTSC biased a bit (60Hz) just remember you are on 50Hz.

Will be interesting to see if the LCD's display differently when the A3000 is outputing an NTSC 60Hz signal.

Good luck
TC :wink:

Re: A3000 640x512 interlaced mode on PC VGA monitor

IF you really want to use it on a lcd panel, then a good measure is using a LCD-TV! It will sync down to the desired 50Hz vertical refresh.

Re: A3000 640x512 interlaced mode on PC VGA monitor

Bah, NTSC interlace is just as bad. Haven't tried any tests yet, haven't got any way of transferring from PC to Amiga sorted out yet. I'll stick a floppy drive in and give it a go.

Piccie uploaded to PhotoBooth topic:- viewtopic.php?f=89&t=2085

Have no room for any more displays so will have to get all my miggy's talking to the LCD's somehow.

Re: A3000 640x512 interlaced mode on PC VGA monitor

@ SJBUK

You might want to read here m8!

Kin