tjt@hocda.UUCP (T.THOMPSON) (09/16/83)
I have a friend that is renting a color TV for use with his VIC-20. I told him about the monochrome monitor I got for my Apple for $90, and he is very interested is getting such a beast and connecting it to his VIC-20. Ignoring color, the problem is that the VIC-20 puts out an RF signal that goes directly to the antenna of a TV. Does anyone know if it is possible and how easy it is to get at a signal inside the VIC-20 that can fed directly to a monitor? Thanks much... ===Tim Thompson===AT&T BL/Holmdel===hocda!tjt===
veach@ihuxl.UUCP (09/20/83)
My VIC-20 outputs video, a small black box in the cable between the VIC and the TV converts it to RF. Thus, to use a monitor connect it directly to the VIC's output. -- Michael T. Veach ihuxl!veach
dya@unc-c.UUCP (09/20/83)
References: hocda.284
Or anywhere else, for that matter, it's easy to get at composite video.
Beware, however, that some CV's are more "conditioned" than others; for
example, you do need a buffer amplifier for the Ataris.
The Commodore VIC-20 uses the Aztec video RF modulator. I believe the
video input is pin # 3. Get a scope and start probing around for anything
that looks like composite video.
The sync tips must be most negative. Be sure to decouple this with at
least 100 microfarads, and observe polarity (usually, and in the Aztec
case, the + mark goes to the computer side. Coax cable must be used to
keep out nasties.
If you are feeling ambitious, put in an opamp buffer with some gain and
filtering (corner frequency of 4.5 mc/s). This will improve crossmodulation.
Judging by what most colour computer manufacturers use to generate the
colours, this result may not be adequate.
ONE MORE THING: Be sure to unhook the video input to the modulator itself,
whatever it is. Computer manufacturers generally avoid using any kind of
double balanced mixer in their equipment to inject the sound carrier. Consequently,
it is possible to get a gross 920 kc beat from the sound inject circuitry
(ATARI users, NOTE !!!)
Any specific questions, just send mail
{ duke!mcnc!unc-c!urp!dya }
-- David --porter@inuxd.UUCP (09/21/83)
The simplest and easiest way to hook up a VIC 20 to a monitor is simply to buy a monitor cable and plug it into the back of the VIC instead of the modulator. If you are too cheap to buy a cable, simply reference the appendix in the back of the users manual you got with the computer. It shows a pinout for the Audio/Video connector. If you have a B&W monitor you will want the luminance signal to feed to the video in of the monitor. If you have a color monitor, hook up the video out signal to the video in of the monitor. The same goes for audio out. The DIN connectors are available at Radio Shack. If you have a Commodore monitor, you can get even a better picture by hooking both the luminance and video out signals to the rear of the monitor. That's the next best thing to RGB. If there are any further questions, please post them to net.micro.cbm. - Jeff Porter AT&T Consumer Products Indianapolis (inuxd!porter)
Trow.pa@PARC-MAXC.ARPA@sri-unix.UUCP (09/27/83)
The VIC-20 does not put out an RF signal. It puts out raw video that a plug-in modulator converts to RF. The pins of the audio/video connector are numbered 1-4-2-5-3 clockwise looking at the back of the computer. Pin 2 is ground and pin 4 is 75-ohm composite video. This video signal can be connected directly to any standard monitor. The level (about 0.5 volts) is lower than normal but not too low for most monitors. Jay