From - Sun Feb 9 16:09:57 1997 Path: jupiter.dnai.com!news.c2.net!re.hotwired.com!news.sprintlink.net!news-ana-7.sprintlink.net!news-pull.sprintlink.net!news.sprintlink.net!news-peer.sprintlink.net!www.nntp.primenet.com!nntp.primenet.com!news.texas.net!uunet!in1.uu.net!206.66.12.35!news-in.iadfw.net!usenet From: ckraft@airmail.net (Colin Kraft) Newsgroups: rec.games.video.arcade.collecting Subject: Re: HELP!!!!!!! Monitor Repair Date: Sat, 08 Feb 1997 02:28:32 GMT Organization: INTERNET AMERICA Lines: 77 Message-ID: <5dgh28$6ek@library.airnews.net> References: <01bc14a6$01a8d620$63e32581@john-note> Reply-To: ckraft@airmail.net NNTP-Posting-Host: fw9-5.ppp.iadfw.net X-Newsreader: Forte Free Agent 1.0.82 "John Butler" wrote: >This brings up a new point. Is it possible on a vertical monitor to put a >4PDT switch in a line somewhere to switch which end is the "top" of the >screen? I think I remember someone mentioning this. Thanks for all the >help. Yes it is possible to do this: How to flip your picture screen (without physically flipping it). On the back of every monitor, right behind the tube, is a thing called the yoke. The yoke has 4 wires that attach to it. By reversing these wires you can "flip" or invert the picture screen by 180 degrees. This comes in handy since there is no set standard in arcade games as to which way the game should be orientated on the monitor. For example, I recently decided that I would like to have Donkey Kong in my Dig Dug cabinet. When I installed the Donkey Kong and powered it up, the picture was upside down! Some boards have the inversion feature via a dip setting but this is the exception in many cases. Like I was saying earlier, there are 4 wires attached to the yoke. Two of them handle the X deflection, the other two handle the Y deflection. It is important not to mix the X signals with the Y signals. To find out which wires are X, which are Y, take an ohmeter and ohm out two wires at a time until you find continuity between a pair. Once you have found the two pairs you are ready to install a switch. When I did this job I went down to Rat Shack and bought 2 DPDT (double pole double throw) switches. You could just buy one FPDT (four pole double throw) but these are harder to find and Rat Schack being as feeble as they are, does not carry them. One switch gets hooked up to the X signals, the other switch inverts the Y signals. Now I will try a beautiful ASCII portrait: 1 C 2 3 C 4 The above is a picture of the terminals of the DPDT switch. First you need to run a jumper between the contacts so that "1" is jumpered to "4" and "2" is jumpered to "3" and form a criss cross so to speak. Next you need to cut your yoke wires (leave room on the yoke side so that you can connect it back!). You should now have two wires that go into the yoke, and two that go to the monitor's chassis or neck board. The wires that you just cut that go to the yoke will be the output wires, the others will be the input wires. Next connect one of the input pair of wires (the ones that go to the chassis) to "1". Connect the other wire that goes to the chassis to "2". The "C"s stand for "common" and these will be your outputs. Run *one* wire from each "C" back to *one* cut wire that goes into the yoke. You remembered to leave enough room to connect the wires with a wire nut didn't you? So now you have the signal coming from the chassis, going to your switch, then going back into the yoke. Use wire nuts or something suitable to splice the wires together and keep them from shorting out. That's it for half of it, now you need to do the same thing for the other pair of wires. It's really quite simple. One word of caution: make sure you power down your game before you flip your switch. Although you may be able to flip it on the fly, it is not recommended and could damage the monitor. So turn the power off first when flipping. That's it, hope this helps. It's defintely a lot easier than physically flipping a monitor especially if you have 2 games in one cab like my Dig Dug/Donkey Kong cab. Colin Kraft ckraft@airmail.net