Apple IIgs has a bench test monitor

Thorvald

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Well after the issues with my Defender, I turned my old IIgs monitor into a test bench. Works pretty well except for sync issues.

Wiring is easy, db15 and just colour to colour, sync and ground.

However with Defender being individual sync and the IIgs being composite sync (but seems to accept Hsync alone just fine), I find the horizontal sync wayyyyyy to sensitive to adjust on the back of the IIgs monitor. In fact I can almost never get a picture to sit perfectly still, but I can at least see that everything is working.

Has anyone found a way around this or a sync combiner that may solve this?

Thanks
Tim
 
I use a IIgs monitor as a bench monitor. Aren't those just the greatest little monitors?

Your problem is that Defender is positive sync. Most other games (and the Apple II monitor) use negative sync. Invert the sync signals with a 7404 or similar. Failing that, you can modify the board to output negative sync - it's documented online.

-Ian
 
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