hansb@ariel.unm.edu (Hans Bechtel) (10/24/87)
I have a commodore 1702 color monitor instead of the regular amiga monitor. Currently, I have the composite output of my 1000 going through the back of my monitor (and it looks reasonable!) but I had heard that you could hook up a cable from the rgb port that would provide "proper" (and better) color with a little more clarity. How can I build such a cable? Where can I get one? etc.... Hans Bechtel "in spanish, 'amiga' means girlfriend..."
erd@tut.cis.ohio-state.edu (Ethan R. Dicks) (10/26/87)
-------- eat me ---------- I have such a product, but I do not have the installation instructions as of yet :-( The solution that I bought, long ago, is the board and cable from Digitek, a purveyor of C-64 hardware. I have not installed it yet, because I bought it from a friend who had a 1701, but never installed the board. I have a 1702 and the monitor circuit boards are different. With the Digitek board, you solder a cable with a DB9 on one end through a hole in the monitor to their board, and then solder some wires to the circuit board in the monitor. I checked the cable from the computer to the board and apparently, the intensity signal is not wired, giving 8 colors, not 15. There are two other hitches with their product. The first drawback is that in the ORIGINAL instructions, the installation procedure instructs you to remove one of the RCA style jacks from the panel on the back of the monitor. This disables the CHROMA-LUMA data input set and the switch on the monitor switches back and forth between NTSC and RGB inputs. Digitek's technical support number provided me with an alternate set of installation instructions which permit, with some restrictions, all THREE input sets into the monitor. The other drawback is the sync signals are inverted from the Amiga. One looks for negative logic sync and the other looks for positive logic sync. If you look on the back of a 1080 monitor, there are switch positions for both. I have built a DB23 to DB9 converter box with optional sync logic inverters (switch selectable), but after a month of waiting, I still have no installation instructions. I will post on the net the results of my efforts, if this topic generates any interest. For specific product detail, contact Digitek at (813) 933-8023 (in Tampa FL) Disclaimer: I am not even happy with them and I still am recommending them. (with a capital CAVEAT EMPTOR) ------------------------------------------------------------------------------- The above which you may or may not have read, may or not be true, and may or not be representative of characters real or imaginary... For a further explanation of the above, see your local philosopher... ...cbosgd!tut!erd -------------------------------------------------------------------------------
cmcmanis%pepper@Sun.COM (Chuck McManis) (10/26/87)
In article <1709@charon.unm.edu> hansb@ariel.UUCP (Hans Bechtel) writes: > > I have a commodore 1702 color monitor instead of the regular amiga > monitor. Currently, I have the composite output of my 1000 going > through the back of my monitor (and it looks reasonable!) but > I had heard that you could hook up a cable from the rgb port that > would provide "proper" (and better) color with a little more clarity. > How can I build such a cable? > Where can I get one? > etc.... Actually it takes more than a cable, it takes some active circuitry too. I have found that the composite video from my A1300 GenLock is *lots* better than the composite video coming out of the machine. All in all you might be better off taking that route. One for Commodore : Any chance that you folks would make a RGB -> Monochrome adapter that plugs into the A1000 RGB port? I suppose I could buy a 500 and transfer my files over there, but I really want to know how a tool I wrote in Hires looks on it's mono output. --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.
grr@cbmvax.UUCP (10/29/87)
In article <31952@sun.uucp> cmcmanis@sun.UUCP (Chuck McManis) writes: > In article <1709@charon.unm.edu> hansb@ariel.UUCP (Hans Bechtel) writes: > > > > I have a commodore 1702 color monitor instead of the regular amiga > > monitor. Currently, I have the composite output of my 1000 going > > through the back of my monitor (and it looks reasonable!) but > > I had heard that you could hook up a cable from the rgb port that > > would provide "proper" (and better) color with a little more clarity. > > How can I build such a cable? > > Where can I get one? > > etc.... To get better output, you would have to modify the composite color encoder circuitry to provide a buffered luminance output. You would then feed this output and the regular composite output into the separate luma and chroma inputs on the 1702 monitor. This should give give better sharpness than regular composite output, but it will still be considerably inferior to a real RGB monitor. > Actually it takes more than a cable, it takes some active circuitry too. > I have found that the composite video from my A1300 GenLock is *lots* > better than the composite video coming out of the machine. All in all > you might be better off taking that route. > > One for Commodore : Any chance that you folks would make a RGB -> Monochrome > adapter that plugs into the A1000 RGB port? I suppose I could buy a 500 and > transfer my files over there, but I really want to know how a tool I wrote > in Hires looks on it's mono output. I've seen what were supposed to be RGB to monochrome conversion cables for the Amiga. I don't know quite how they work or what kind of quality one gets. It probably wouldn't be too hard to put a little switch on the MC1377 video encoder circuitry that would manually disable the color burst and bypass the bandwidth limiting luma delay line. I haven't looked at the chip spec closely, so there might be some problems that would make it more complicated than it appears. The as-is composite color output from the A1000 doesn't look all that bad. You get grey scales and a little more bandwidth/sharpness than on a color monitor. You also get some hatching from the color subcarries, but this actually substitues a textured appearance for the color, It's generally not offensive. Any video hackers out there want to play with this stuff? -- George Robbins - now working for, uucp: {ihnp4|rutgers|allegra}!cbmvax!grr but no way officially representing arpa: out to lunch... Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)