S-Video from the VIC

[SparkyNZ]

What result do you get, when you connect your luma to pin 5 of the video connector instead?

I read 120 pF and 3.9 µH. This would correspond to a transition frequency of ~7.4 MHz.

I just gave it a try. The result is exactly the same.

[Mike]

An analog passive delay line of 150 ns on the chroma signal might do the job, but it would then become the most expensive part of your mod.

One candidate would be the TZB78-7 from Rhombus Industries, a 10-tap 200 ns passive delay line with 75 Ohm impedance in a 14-pin DIL package.

You wire it as follows:

chroma in (from VIC): pin 1
GND (from VIC): pin 14
chroma out (to TV): pin 10 (140 ns) or pin 6 (160 ns), whatever is better
GND (to TV): pin 8

[SparkyNZ]

An analog passive delay line of 150 ns on the chroma signal might do the job, but it would then become the most expensive part of your mod.

One candidate would be the TZB78-7 from Rhombus Industries, a 10-tap 200 ns passive delay line with 75 Ohm impedance in a 14-pin DIL package.

You wire it as follows:

chroma in (from VIC): pin 1
GND (from VIC): pin 14
chroma out (to TV): pin 10 (140 ns) or pin 6 (160 ns), whatever is better
GND (to TV): pin 8

Thanks Mike. I've just sent an email for a price quote from Australia.

You know.. if I wasn't intending to buy a Mega-Cart, I would be hoping there was something like the Turbo Chameloon cartridge for the Vic so I can just get straight VGA out of the Vic.. but then I'd have the same dilemman with my C64 I guess.

I've just grabbed my AverMedia video-USB converter. That has an S-Video input on it as well..

Interestingly enough the image is way better! It wouldn't work at first but now it is.. so it could be better (or worse) if I buy another (smaller) TV. Hmm.. I guess I won't find out until I buy one..

[Mike]

Hi, SparkyNZ,

sorry I have to admit I erred by nearly a factor of two in the necessary delay time, somehow the C64 NTSC pixel clock crept into my thoughts.

The PAL pixel clock of the VIC-20 is 4.43 MHz, which incidentally is also equal to the colour carrier frequency, this corresponds to a 225 ns delay.

So you'd better use the TZB90-7 instead, with a maximum of 300 ns delay, and wire as follows:

chroma in (from VIC): pin 1, as above
GND (from VIC): pin 14, as above
chroma out (to TV): pin 10 (210 ns) or pin 6 (240 ns), whatever is better
GND (to TV): pin 8, as above

Greetings,

Michael

[SparkyNZ]

Hi, SparkyNZ,
sorry I have to admit I erred by nearly a factor of two in the necessary delay time, somehow the C64 NTSC pixel clock crept into my thoughts.

Thanks Mike. I haven't ordered one yet. I'll wait and see what happens when I buy a second-hand TV. I may be lucky.. If it does the same thing as it does on my plasma, then I know what to do.

There are also some S-Video to HDMI converters around. That could even be another option for me too.. but I would prefer straight S-video connection to a TV (less wires, less AC adapter bricks.. built-in speakers etc). I could find an older CRT TV too but.. yuck.. nah.. some retro technology I just can't go back to. Slim flat screens only for me, thanks

If I buy and see a few TVs to get a working one.. I may have to start my own compatability thread (Only kidding)

[SparkyNZ]

Hi Folks. Well I am really really happy. I took a gamble and bough at 15" Sharp LCD TV. I connected my modded USA NTSC Vic-20 and it works great!

There's still some ghosting similar to what I had with my 50" plasma but its not nearly as noticeable.

I'm still keen to try and correct it tho, Mike. Haven't heard anything back from Australia in relation to those Rhombus components but I could try elsewhere in the world..

[mikem]

I modded my Gold label 2 prong Vic and all went good thanks for the instructions!

Which instructions did you use for the 2 prong version mod?

thanks

[Mike]

This one: 'S-Video mod on PCB model 324002-02 rev D'.