Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-crg!mordor!sri-spam!sri-unix!hplabs!tektronix!uw-beaver!tikal!hplsla!janh From: janh@hplsla.HP.COM (Jan Hofland) Newsgroups: comp.sys.cbm Subject: Re: GEOS and composite video Message-ID: <960002@hplsla.HP.COM> Date: Wed, 10-Dec-86 11:55:38 EST Article-I.D.: hplsla.960002 Posted: Wed Dec 10 11:55:38 1986 Date-Received: Mon, 15-Dec-86 04:21:58 EST References: <4073@columbia.UUCP> Organization: HP Lake Stevens Lines: 21 [] I, too, have found the composite video text display marginal when using GEOS. My solution turned out to be a hardware modification to the C64. My machine is an early version (version 1, I think). I noticed that the more recent vintages use video interface circuits built into the RF modulator, rather than the transistors, resistors, and capacitor circuitry mounted directly on the pc board. What I did was to build a circuit that goes between the VicII chip and the DIN video output connector that duplicates what is happening inside the newer version RF modulator. The most significant differences are the use of a locally regulated power source and separate emitter followers for the composite video, lumenance, and chroma outputs. Jan Hofland Hewlett Packard Lake Stevens Instrument Division 8600 Soper Hill Road Everett, Wa. 98205 ..hplabs!hp-pcd!hplsla!janh