Apple IIgs Video Sync Question

4 posts / 0 new
Last post
Offline
Last seen: 13 years 6 months ago
Joined: Sep 21 2008 - 00:13
Posts: 61
Apple IIgs Video Sync Question

Does anyone know what type of sync the Apple IIgs outputs (on the RGB output)? Positive or negative. If negative how do you convert it to Positive.

Offline
Last seen: 13 years 6 months ago
Joined: Sep 21 2008 - 00:13
Posts: 61
Just asking because I'm looki

Just asking because I'm looking at picking up a cheap Atari ST RGB monitor (SC1224), locally, to use with my Apple IIgs via an adapter. In the manual it IDs the monitor as "R G B (Positive)" I think I read a while back that some one with much trouble got an old Commodore RGB monitor to work with the IIgs. The main problem was the difference in sync polarities.

eeun's picture
Offline
Last seen: 1 year 1 day ago
Joined: Dec 19 2003 - 17:34
Posts: 1895
According to [b][url=http://s

According to this site the sc1224 works okay with the IIgs with a pin-to-pin adapter.

I was looking at this guy's adapter for use with my STe's RGB out. It's a scan doubler for the horizontal sync, which will let you use your RGB-output computer on a VGA monitor. He was asking around $70 for the adapter, and could adapt the input connector to your needs.

There's a few on ebay as well that claim to take just about any 15KHz input and double it for VGA out, but I've read mixed results with older computers.

Offline
Last seen: 13 years 6 months ago
Joined: Sep 21 2008 - 00:13
Posts: 61
That's good news. I'm goin

That's good news.

I'm going to build a 15kHz RGB to VGA (scan doubler) converter eventually (and long with a list of other adapters that one might find useful), but this is just a quick fix solution until I get around to building one. I haven't played around with my Apple IIgs much due to the migraine inducing color composite video, and the loud PSU (fix is on the way for the PSU). Thanks for that link. I didn't currently know about that one. I'm pretty sure the scan converter design I want to do is different then his (the internal circuit). Not sure how much it would cost to make either, or which one will be better. It's down to $48 and shipping, Not bad.

Results will vary depending on the computer and the monitor you use. CRT monitors seam to be more forgiving then LCD monitors (for variation in the signal and being able to adapt to them). No matter the advantages of CRTs and how much I love tubes at the end of the day LCD are a win in my book. That and I can't stand the high pitch sound they make (CRTs). I can hear them rooms away.

Log in or register to post comments