A2000 not outputting @ 15KHz video?

[towmater]

I've been using an NEC 1970VX lcd without issue directly on an Amiga 500, and an Atari ST. The Amiga 2000 that I just picked up, however, displays video for a few seconds then flashes "no signal."

 

Any suggestions as to what might be different? I thought it might be a KS2.1 monitor definition in Workbench, though the problem still happens when booted to an older workbench by floppy.

 

The A2000 works fine with a GBS video converter onto an HDMI monitor, but it is not as sharp and not the monitor I'd prefer, I'd rather use the lcd flat screen & can't afford the internal scan doubler just yet.

 

[amiman99]

Maybe it's set to PAL 50Hz, most PC monitors don't like 50hz.

[towmater]

J102 is closed, so I think it is NTSC.

J200 - no effect on the issue.

Edited August 21, 2016 by towmater

[amiman99]

Connect the BW composite video to TV and check if that works, then check the screenmode settings and see if it set to something unusual.

You could also boot with any game and see if it works.

[towmater]

So the bizarre solution to this is to start the A2k with the monitor connected, immediately disconnect the vga cable the moment the signal appears, wait five seconds, then reattach the vga and the monitor works properly. Any variation to this procedure gives me "no signal."