S-Video conversion possible as plug-and-play solution?

Modding and Technical Issues

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mrr19121970
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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Thu Mar 03, 2016 8:27 am

That's only an opion, and I have a differing one. Doesn't make mine or Ray's wrong just as they are different?

Let's humour the idea further? Would it be possible? What would be needed?

Shopping list
1 x Pack of test probes http://www.ebay.com/itm/121901525743
1 x 330ohm resistor
1 x 0.1uF ceramic cap
1 x precision socket (snip off pin 2 - better still. Insulate with heatshrink???)
1 x s-video jack *
2 x rca jack (or 3.5mm headphone socket) *
* or rca stereo plug and s-video cable directly
1 x bits of wire
1 x some shrink wrap

Recipe for octopus cable
A. VIC-I PIN2-> Hook -> 330 ohm resistor + 0,1uF ceramic cap -> s-video chroma (shrink wrapped for insulation)
B. Video Out PIN5 -> Hook -> s-video luma/sync
C. Video Out PIN3 -> Hook -> audio left & audio right
D. Any GND -> Hook -> s-video ground 1&2 + audio left+right ground

Recipe for plug and play
Remove VIC-I from socket, insert into new socket with PIN2 removed. Connect Hook A. Insert back onto mainboard
Connect Hook B, C and D
Enjoy s-video using standard cable and audio jacks or black and white only composite using original video output.

VIC-1 Pinout
Image

Video Out Pinout
Attachments
VIC-I Video out.jpg

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mrr19121970
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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Wed Mar 23, 2016 3:09 pm

So not exactly as I planned it. But this is how it works. Removed your vic-i from the socket. Add the 2nd socket with you capacitor and resistor. Put the vic-i back in the socket. Little wire goes over the tin edge and between the fingers on the lid and out of the case. Here you join the chroma with a 1 pin dupont connector to the 5 pin connector.

To reverse simply pull the vic-I and the 2nd socket and put the vic-I back on the board. Same cable can be used for composite only.

Screen without mod (just composite)
rps20160323_220327.jpg
Screen with mod
rps20160323_220305.jpg
Mod
Socket with PIN#2 removed and modding wire soldered onto top. 0.1uF ceramic capacitor and 75 ohm resistor in series (insulated with heat shrink tubing) leading to a 1 PIN DuPont female connector outside the case (secured with cable tie on the eyelet next to the datasette edge connector)
rps20160323_220219.jpg
Modding wire comes over the top of the 'tin' and between the 'fingers of the lid' and around the tin so that the insulated capacitor and resistor are between the 'tin' and serial/video connectors. The standard 5 pin video wire is connected 2 GND, 3 audio and 4 luma. There is a male DuPont connector directly to the chroma
rps20160323_220243.jpg
Last edited by mrr19121970 on Thu Mar 24, 2016 7:24 am, edited 6 times in total.

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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion » Wed Mar 23, 2016 3:48 pm

I still see a lot of dot crawl.

For your mod to be effective, the chroma signal must no longer make it to the board of the VIC-20. Did you cut that pin on your 2nd socket?
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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Wed Mar 23, 2016 10:56 pm

Yes. The pin is cut on the socket for pin 2. With the DuPont pin disconnected the image is 100% black and white. Maybe just my phone, but IRL the difference is like night and day.

Before
2016-03-24 08.43.50.jpg
2016-03-24 08.43.50.jpg (20.93 KiB) Viewed 6943 times

After
2016-03-24 08.42.41.jpg
2016-03-24 08.42.41.jpg (34.27 KiB) Viewed 6943 times

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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Fri Mar 25, 2016 4:26 am

I did another machine. This time I used 360 ohm and not 75 ohm like before.
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rps20160325_112246.jpg
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Re: S-Video conversion possible as plug-and-play solution?

Post by vicist » Fri Mar 25, 2016 6:02 pm

Now this looks like something I could use on my Pet-Key Vic. (Keep me away from that darn soldering iron)

How much would you want to supply me with:-

modded socket + modded video cable + postage to UK?

Can you show the other end of the modded cable (the bits that connect to your tv).

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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Sat Mar 26, 2016 12:00 am

If your vic-i is socketed then no issue. I will supply the bits. I can make your cable up to 5 long. This is how mine looks...
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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion » Sat Mar 26, 2016 12:34 am

The moiré pattern confused me on your first photos.

The last shots with Donkey Kong seem just perfect.
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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Sat Mar 26, 2016 6:27 am

Your custom cable for both hard mod and plug'n'play mod will look like this.
20160326_132332.jpg
For vic20 cr with hard mod you simply connect the 2 dupont 1p on the 5pin din. For the vic20 with the plug'n'play mod you connect the dupont from the vic-I to the cable. Job done.

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Re: S-Video conversion possible as plug-and-play solution?

Post by vicist » Sun Apr 03, 2016 1:19 am

Received my 'Plug 'n Play' mod and cable from @mrr19121970 yesterday.

How easy was that to do? Couldn't be simpler. :D

Lever out my Vic I chip, insert socket with mod wire attached and replace Vic I chip. Connect to monitor using custom cable and et voila - S-Video. 8)
(This mod was performed on my original 2-prong PET key VIC and needed a 1/4 turn to the left of the left hand video adjuster to achieve correct colour output)
The mod cable supplied also allows me to use my S-Video modded VIC cr with my monitor.

What a great solution for anyone with an original 2-prong PET key VIC who wants S-Video (or a VIC cr version with socketed Vic I chip who doesn't want to get involved with a soldering iron).

Highly recommended. Thanks Mike.

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Re: S-Video conversion possible as plug-and-play solution?

Post by Boray » Sun Apr 03, 2016 3:04 am

So, how much does it cost?
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Re: S-Video conversion possible as plug-and-play solution?

Post by vicist » Sun Apr 03, 2016 6:01 am

Charge for me personally was going to be €20.

This was for the socket and wire mod, the modded cable for connection and postage to UK. I paid extra for an additional modded cable to be made (cables were 1.5m in length and were for universal use on both socket mod and hard mod machines, both for tv and monitor use).

Cost would probably depend on length and type of cable (if needed).

I know you have some old 2-prong pet key style VIC's and this is an easy, no fuss way of getting S-Video out of them.

Go for it. You know you want to. :wink:

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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Sun Apr 03, 2016 9:31 am

Boray wrote:So, how much does it cost?
I am offering on amibay:

http://www.amibay.com/showthread.php?81 ... dification

you can pm me here too if you need one.

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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 » Sun Apr 03, 2016 1:34 pm

vicist wrote:
What a great solution for anyone with an original 2-prong PET key VIC who wants S-Video (or a VIC cr version with socketed Vic I chip who doesn't want to get involved with a soldering iron).
Well I also did it for my own vic20 cr model. It is not that I am afraid of my soldering iron. I consider the suggested mod of removing / adding components and cutting traces not in the spirit of retro computing. Ray Carlson's mod drilling a hole and adding a 8 pin din was like a tattoo for me (cool at the time but something to regret in the long run).

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Re: S-Video conversion possible as plug-and-play solution?

Post by vicist » Sun Apr 03, 2016 2:07 pm

Just the thought of having to desolder the vic chip and solder in a socket for it sends shivers down my spine. I would never have attempted that. Besides, your socket mod wasn't available when I decided to 'hard mod' my cr VIC boards.

As for my pet key VIC-20, I feel your mod is the only way to go.

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