From - Tue Jun 18 17:39:24 1996 Path: masters0.news.internex.net!newshub.internex.net!newshub1.internex.net!news.Stanford.EDU!bloom-beacon.mit.edu!newsfeed.internetmci.com!uwm.edu!cs.utexas.edu!news.ti.com!bugs!a908570 From: keay@tiuk.ti.com (John Keay) Newsgroups: rec.games.video.arcade.collecting Subject: Re: TECH: weak sync signals Date: 18 Jun 1996 08:03:48 GMT Organization: Texas Instruments Ltd. Lines: 27 Distribution: world Message-ID: <4q5nt4$5gc@tilde.csc.ti.com> References: <> Reply-To: keay@tiuk.ti.com NNTP-Posting-Host: bugs.tiuk.ti.com > In doing some Jamma conversions, I've come across three games which seem to > fail to sync on my (raster) monitor, and one more which sometimes syncs > horizontally (but not vertically), and sometimes fully fails to sync. > > I thought I'd convinced myself that it wasn't my monitor's fault, but now > I'm beginning to think that maybe my monitor needs stronger sync signals > for some reason. > > Any suggestions? Yes, I've had this a couple of times as well. The boards work okay on some monitors but don't sync up well on others. The sync signals are easy to buffer. Sync signals (even HSYNC) have a much lower frequency than the RGB signals and are digital rather than analogue so unlike the RGBs they are easy to buffer and invert. Use a couple of TTL inverters in series (or almost any other spare TTL chip you have lying around) to buffer them. This worked for me (somewhat unexpectedly) on two of my boards, so I added the buffering chip to my JAMMA conversion harness for that game. * John Keay ! TMS320C80 design * * work: keay@tiuk.ti.com ! Texas Instruments Ltd. * * home: john@keay.demon.co.uk ! Northampton, U.K. * * Disclaimer: All opinions expressed herein are personal. etc etc *