Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!usenet.ins.cwru.edu!falstaff.mae.cwru.edu!jb From: jb@falstaff.mae.cwru.edu (Jim Berilla) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Video 7 Requires Reset to operate Keywords: vga Message-ID: <1990Dec28.173105.25022@usenet.ins.cwru.edu> Date: 28 Dec 90 17:31:05 GMT References: <15395@ogicse.ogi.edu> <1990Dec27.182847.1451@usenet.ins.cwru.edu> Sender: news@usenet.ins.cwru.edu Distribution: usa Organization: Case Western Reserve University Lines: 36 Nntp-Posting-Host: falstaff.mae.cwru.edu In article <1990Dec27.182847.1451@usenet.ins.cwru.edu> I write: > >In the Zenith monitor, the cable with the RGB signals goes to a connector >on the video board. The connector is crummy and doesn't make good contact. >The video signals are terminated on the video card with 75 ohm resistors. >As the contact resistance of the connector changes, it causes the video >signal at the board to change, causing the characters to flicker and >change colors. After re-reading this, I find that it's confusing. The connector in question is _inside_ the monitor. It's not the 15 pin connector that goes to the vga card. You have to take the monitor apart to get to it. Two cautions about this. First, Zenith will probably give you a hard time about future warranty work if they find out that you took their monitor apart. (I will never take anything back to them for warranty work again, but that's my opinion.) Second, like most electrical stuff, there's high voltage in there. Standard warnings apply. >In my case, the red signal connector had about 30 ohms of resistance. >The paradise card detects a monichrome monitor by the fact that the red >video signal isn't terminated. (monochrome monitors use only the green >video.) So, the 30 ohm resistance of the connector plus the 75 ohm >termination was high enough that the card thought that the video signal >wasn't terminated, and started up in monochrome mode. I tried resetting >the color pallet, but it still wouldn't let me disable gray-scale summing. > >My solution was to take apart the connector and squeeze the contacts on >the connector together to make better contact. It took a few times before >I got them squeezed enough to be reliable. I got very close to ripping >out the connector and soldering in the cable. -- Jim Berilla / jb@falstaff.cwru.edu / 216-368-6776 "My opinions are my own, except on Wednesday mornings at 9 AM, when my opinions are those of my boss."