Using a VIC with a real Commodore monitor?

rhurst · Post by **rhurst** » Mon Jan 26, 2009 4:18 pm

Sorry for "necromancing" this thread ... it was the only search result with "1902" in it. I just got a nice new 1902 monitor from ebay today, and it works great with my C64c and Plus/4, and soon to arrive C128.

But, I cannot hook it up to my original VIC 20 (older design, two prong power, flat keyboard, if that helps any) as it only has the RF Modulator, and the 1902 cable has two extra pins on the DIN-side. Is there a compatible cable for VIC 20 for Commodore 1902 monitor, or can I just "clip" the extra two pins and make it "fit" -- heh, heh.

ral-clan · Post by **ral-clan** » Mon Jan 26, 2009 4:31 pm

Does the 1902 have RCA type Luma-Chroma-Audio inputs or even video/audio inputs?

You could just snip the cable off the RF modulator (if you aren't going to use it again, solder some male RCA jacks on the exposed wires, and have a DIY VIC-20 DIN to luma-chroma-audio cable.

I found this reference to the pinouts of this monitor:

I have one of these monitors that I am about to give away. It came with a converter cable to go from 6 pin din to DE9Male TTL Hercules monochrome adaptor on an IBM PC or clone. The wiring I have is:

DE9Male - DIN6Male
1-----shield-----6
2-----white------3
3-----n/c
4-----n/c
5-----n/c
6-----brown------4
7------red-------5
8-----green------1
9-----black------2

din6male, facing from outside to inside connector:

1 V 5
6
2 4
3

Don't know how accurate or helpful this info is (probably not very). I found it here:

http://www.vintage-computer.com/vcforum ... t-990.html

Someone on that thread mentions the 1084 shares the same socket and links to this pinout reference:

http://pinouts.ru/Video/C1084a_pinout.shtml

Judging by that it's an RGB video port, and I'm not sure if you could or even should hook the VIC-20's video output into that.

rhurst · Post by **rhurst** » Mon Jan 26, 2009 6:10 pm

Interesting about the Commodore 1084 pinout... it may apply.

I am not looking to plug it into the 9-pin RGB connector, but into the RCA composite ports: red-yellow-white split cable end. I would rather just buy a pre-made one, but I fear none exist. I also read something about modding the VIC to us a SCART connector, but what is that and what does it do?

So I googled some more and found this reference in a post:

Code: Select all

  ___ ___
 /   v   \
( 3     1 )
 \ 5   4 /
  \__2__/

Pin 1 is +5V - should not be used (drives the RF?)
Pin 2 is ground - required.
Pin 3 is audio out - required if you want sound.
Pin 4 is 50 ohm video out (low?) - normally the one used.
Pin 5 is video out (high?)

So, you should use pins 2, 3 and 4 for a composite + audio cable. I can't remember if this is the view from the computer female or from the cable male.

Okay ... but how does that wire to RCA composite cables? Does this make sense to you hardware gurus?

Also found this reference for Sega Genesis A/V cable:
http://www.stageselect.com/News/NewsVie ... newsid=174
Looks like VIC may use a different pinout, but this guide shows the correct parts, no?

ral-clan · Post by **ral-clan** » Mon Jan 26, 2009 8:41 pm

Commodore did make a cable that worked on VICs and older C64s which allowed them to be hooked up to monitors with RCA VIDEO/AUDIO inputs, or the chroma/luma/audio inputs of 1702 monitors (and Amiga monitors).

'm sure you can still buy them online....but perhaps the ones available now are for the later model C64, which had a slightly different DIN connector.

But, it's super easy to make a VIC monitor cable - one that connects from the VIC's DIN monitor port to the RCA inputs on the back of your 1902 monitor (or the VIDEO/AUDIO inputs of a modern TV). I'm sure there are already a bunch of threads describing how to do this on Denial.

The easiest way is just to go to your local electronics parts dealer, buy the proper DIN connector and some cabling containing two wired and a ground shield (or three wires), and two male RCA connectors. With this you can make one yourself according to the diagram you have.

If you can't buy the DIN connector and wire you can simply cut the DIN cable off your RF modulator just before it enters the metal box. If you peel back some of the insulation, you'll find there is a ground shield, a wire for the audio and another for the video (and perhaps another for the +5V power).

You only need the ground, video and audio wires. Basically, you attach one RCA connector each to the audio and video signal wires, and attach the ground shield or wire to the ground (outer sheath) of the RCA connectors.

The VIC puts out full colour composite video via the video pin in that DIN diagram above. The luma and chroma are mixed together inside the VIC and do NOT leave the computer as separate signals (as on the C64).

So a VIC monitor cable can be used with any monitor, TV or even VCR that has a VIDEO/AUDIO input using RCA connectors.

carlsson · Post by **carlsson** » Tue Jan 27, 2009 1:34 am

If you are afraid of soldering, eBay has tons of suitable cables, both 5-pin DIN variants to fit VIC/C64/Atari etc and 8-pin DIN variants for C64/Plus4. Obviously you want the 5-pin one.

One thing to point out is that a composite video signal is connected to the luminance jack and then you toggle some switch on the back of the monitor. Many people get stumpled on this.

Leeeeee · Post by **Leeeeee** » Tue Jan 27, 2009 4:56 am

but how does that wire to RCA composite cables?

The video RCA should be connected shield to pin 2, inner to pin 4.

The audio RCA should be connected shield to pin 2, inner to pin 3.

Lee.

rhurst · Post by **rhurst** » Mon Feb 09, 2009 6:40 pm

The video RCA should be connected shield to pin 2, inner to pin 4.
The audio RCA should be connected shield to pin 2, inner to pin 3.

Went to Radio Shack for the DIN connector and some solderless RCA ends (although I did solder the ends), worked like a charm -- thanks!!

The 1902 monitor has a 3rd switch setting upfront which allows the color to come through on the one composite Yellow video pin -- the middle setting labeled SEP.(arate) works with C64/128 40-column mode -- with the right setting for the 80-column RGB.

PaulQ · Post by **PaulQ** » Mon Feb 09, 2009 7:07 pm

For the record, the RF modulator that comes with the Vic 20 is easily converted into an audio/video RCA jack split. The connections on the PCB inside the modulator are clearly labeled.

rhurst · Post by **rhurst** » Sat Mar 07, 2009 2:45 pm

I have a VIC 20 hooked up to a rather "mint" (if you can call it that) Commodore 1702 monitor -- using the A/V inputs upfront and throwing the switch in the back to use those front ports.

Anyways, the picture comes through nicely with my homebrew cable, with the exception of Black and White background screens. I find I have to either turn the brightness to FULL to see White, but then Black screens are all washed out, and I have to turn the brightness down... whereas the WHITE goes dark and gets greyish.

I thought there was a similar post about this, but I cannot locate it. Any clue as to what to do? TIA!

ral-clan · Post by **ral-clan** » Sat Mar 07, 2009 3:17 pm

Have you already adjusted the pots inside the video section of the VIC to calibrate it for a 1702 monitor? I just remember that whites are pretty grey looking until you do that.

rhurst · Post by **rhurst** » Sat Mar 07, 2009 3:43 pm

adjusted the pots inside the video section of the VIC

I adjusted all the pots inside the 1702 monitor ... are there pots inside the VIC itself?

ral-clan · Post by **ral-clan** » Sat Mar 07, 2009 3:45 pm

Yes, there are two pots inside the little silver box in the VIC-20. There is a thread around here that explains what they do, but it's pretty evident once you start turning them.

Until you make this adjustment, the VIC looks terrible on a 1702.

I'm not aware of any pots inside a 1702 that ever needed adjustment.

In fact, the info on the potentiometers is posted in this very thread you are appending to. Did you read the original message in this thread?

rhurst · Post by **rhurst** » Sat Mar 07, 2009 4:33 pm

the info on the potentiometers is posted in this very thread

HOLY COWABUNGA!!

I re-read this entire thread, and found the two pots it refers to.

I had to continue to tweak both for all these color combinations, until each came through without skewing the picture any:

poke 36879,8
poke 36879,9
poke 36879,10
poke 36879,11
poke 36879,27

The colors are much more vibrant and correct. Only YELLOW comes through a little more brownish (like a tarnished gold metal).

poke 36879,255

But turning up the 1702 brightness a tad makes it look just fine.
This was very helpful, thank you!! Now, can anyone find my glasses, I just had them on a minute ago ...

ral-clan · Post by **ral-clan** » Sat Mar 07, 2009 5:43 pm

Since this question comes up a lot I made a WIKI article:

http://sleepingelephant.com/denial/wiki ... djustments

Post by **Jeff-20** » Sat Mar 07, 2009 6:47 pm

Really nice article!