From - Tue Jun 18 17:39:43 1996 Newsgroups: rec.games.video.arcade.collecting Path: masters0.news.internex.net!newshub.internex.net!newshub1.internex.net!news.sprintlink.net!news-stk-11.sprintlink.net!news-in.tiac.net!news.kei.com!newsfeed.internetmci.com!gordius!jonboy From: jonboy@gordian.com (Jonathan Walton) Subject: Re: TECH: weak sync signals Message-ID: Sender: news@gordian.com Organization: Gordian; Santa Ana Heights, CA X-Newsreader: TIN [version 1.2 PL2] References: <> <4q5nt4$5gc@tilde.csc.ti.com> Date: Tue, 18 Jun 1996 20:03:29 GMT Lines: 30 John Keay (keay@tiuk.ti.com) wrote: : 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. Thanks. I actually thought this up this weekend and tried it out, and sure enough it worked. Actually, after putting the sync buffer on and tuning the monitor H-hold and V-hold, I was able to take the sync buffer off and it still works. I guess I wasn't adjusting the H-hold and V-hold well enough! : 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. Actually, I came up with a better way to deal with some of this. I just make dumb jamma conversion harnesses... ignore sync polarity, RGB polarity, and audio amplification. Then I made three extra jamma pass-throughs. One with RGB inversion stuff, one with audio amplification, and one with a sync inverter/buffer (it's got a switch). They're essentially a jamma socket, about an inch of finger-board, and some chips glued to the side. It works great, and it means I only had to wire all that up once, no matter how many different conversions I make that need them. Anyway, thanks for the input, and happy gaming, Jonathan