Problems using a vintage Sanyo VM4509 monitor with my Apples

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Joined: Jan 27 2011
Posts: 110

I just picked up a 9" Sanyo B&W monitor (model VM4509) to use with my Apple II systems the "old school" way circa 1978. Looks great sitting atop the computer alongside my Disk II drives the way things used to be before affordable monitors came along.

However, I can only get it to display a stable image when hooked to my Enhanced IIe...when I plug it into my 1977 rev.0 II or 1979 II Plus systems the picture rolls like crazy and the V-Hold pot on the monitor can't get it under control.

Why would it be that it works really well with my IIe but not my II or II Plus?
I'm kind of bummed because it's the older systems that I'd want to use it with, not my IIe that has a nice Apple color monitor for regular use.

Any tips would be welcome, thanks!

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Joined: Jan 27 2011
Posts: 110
Re: Problems using a vintage Sanyo VM4509 monitor with my Apples

Oh, and I forgot to mention that both my older Apple II and II Plus display well on the Apple color monitor, so I know for sure that both of the older systems are outputting video just's just the little Sanyo VM4509 doesn't like their output for some reason. But it loves the IIe.

Could it be that the IIe has stronger output signal and the older machines are weaker and therefore the Sanyo (due to aging parts) can no longer lock onto them?

I've also messed with the little pot next to the video output on the II and II Plus motherboards, and while I can see the image getting darker/brighter on the Sanyo it has no effect on the image stability.