From epass@nyx.cs.du.edu Thu Dec 16 10:59:22 1993 Newsgroups: comp.sys.cbm Path: klaava!news.funet.fi!sunic!EU.net!uunet!mnemosyne.cs.du.edu!nyx!epass From: epass@nyx.cs.du.edu (Eric Pass) Subject: SUMMARY: Looking for plans for 80 column cable for 1702 monitor Message-ID: <1993Dec15.171632.11006@mnemosyne.cs.du.edu> X-Disclaimer: Nyx is a public access Unix system run by the University of Denver for the Denver community. The University has neither control over nor responsibility for the opinions of users. Sender: usenet@mnemosyne.cs.du.edu (netnews admin account) Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept. Date: Wed, 15 Dec 93 17:16:32 GMT Lines: 78 Thanks to all who responded to my request for information about building a 80 column cable to attach my C128 to a 1702 monitor. Informative responses were received from: Eric K. Schanberger (schane@rpi.edu) Mark Spacek (spacek@ghostwheel.bga.com) Marko Mäkelä (Marko.Makela@Helsinki.FI) George Page (gpage@nyx10.cs.du.edu) and especially Gordon (GAJ2@psuvm.psu.edu) whose full response is appended below. TEXT IMPORT BEGINS ================== >From GAJ2@PSUVM.PSU.EDU Tue Nov 30 16:05:19 1993 Return-Path: Date: Tue, 30 Nov 93 18:03 EST From: To: epass@nyx.cs.du.edu Subject: Re: Looking for plans for 80 column cable for 1702 monitor >Can anyone provide or direct me to a a set of schematics or parts >list necessary to construct an 80 column cable. I've heard rumours of >such a file existing but couldn't find anything on ccosun.caltech.edu in >For those who are unsure what I'm talking about, an 80 column cable >will connect your 128 to a 1702 or other 40 column monitor and give >you 80 columns monochrome only. Eric- I made this connection between my C128 and 1702 monitor when I first obtained my C128. Although it gives you true 80-column monochrome output, it is very hard to read the letters on the screen. However, it was good enough for me to use many 80-column only programs, such as Dialogue, etc. You will need the following: a D-Sub 9 pin male connector (Radio Shack #276-1427) a D-Sub 9 pin Hood (RS #276-1513) Shielded Phono Plug to Tinned Wire (RS#42-2370) C128 System Guide On page 354 of the C128 system guide is a diagram of the RGBI output socket. When viewed from the back of the computer, pin #7 is the monochrome output, and either one of pins #1 or 2 are the shielded ground connection. If you solder the shielded copper wire from the phono plug wire to the corresponding pin on the D-Sub 9 connector (check to be sure it matches pin #7) and the shield wire covering the phono plug cable to either pin #1 or 2 (I used pin #1) you will then have a monochrome-only 80-column output that plugs into the FRONT RCA video jack on your 1702. You can still keep the composite video and audio connections hooked up to the rear jacks, but you will have to move the slide switch on the rear of the monitor to the FRONT input. (The audio connection on the rear still functions when the slide switch is moved to the FRONT position.) I forgot to mention that the hood slips over the D-Sub 9 pin male plug to prevent shorting of the pins. It is held together by a couple of screws, and it has two screws which can be used to fasten the D-Sub 9 pin connector to the RGBI port on the back of the C128. Hope this info is helpful; if you have any questions, just ask me. Gordon GAJ2@psuvm.psu.edu BTW - If you ever run across an IBM PC "Color Display" monitor, also known as a CGA monitor, you might want to grab it if it is comparably priced... I obtained one of these for $50, and I was amazed to find out that it is pin-for-pin compatible with the C128 RGBI output port! It also came with a D-Sub 9 pin connector, so I didn't have to make a new cable! TEXT IMPORT END =============== -- Eric W. Pass (epass@nyx.cs.du.edu)| Yes, I am published in Dragon Magazine Terminally hooked. | but I'm older now. --------------------------------------------------------------------------- ObDisclaimer: I'm sorry Senator, I don't recall making that statement.