Cassete Vision AV?

[lazzeri]

   Hello,

 

   I was wondering if there´s a composite mod for the Cassete Vision since it´s HELL to get an image due to NTSC-J.  Google didn´t help at all!

 

   The only way I managed to get a (terribly shaky) picture was by using the X68000 monitor that have a (really clunky) TV tuner build-in.

 

   Any ideas? Anyone managed to mod it? Any tips on tuning that beast that does not involve importing a TV or VCR from Japan?

 

   Thank you in advance!

[stupus]

In the usa japanese channel 1 and 2 tune to channel 95 and 96.

It can also depend on the tv as well though how good it tunes in various rf signals.

[carlsson]

As you know, each game contains not only ROM code but also its own CPU, graphics and audio. Most (all?) of them use the uPD777 video game processor which supposedly on its pinout has signals for R-Y, B-Y, Chroma, Video and Sound, possibly even R and G but not B. Assuming this info is reasonably adequate, it should be possible that from inside the console trace the pins for those signals and tap them, just like the built-in circuitry must do to generate the NTSC-J RF signal. However I know nothing about if this is practically doable. I think @slydc has been diving into the Cassette Vision before and may have something to add.

 

https://forums.nesdev.com/viewtopic.php?f=23&t=14568#p176030

[lazzeri]

IT LIVES! 😍

 

Tried it on a Samsung TV.  Nothing.

 

Sharp Aquos TV? Nada.

 

Last desperate attempt: a Fujitsu monitor + TV. Profit!

 

(I’ve setted it to Cable. Worked on Channel 6).

 

I’m a happy camper. 😄

[stupus]

Nice! Looks great!

I definitely notice the tv makes a big difference. 

Like you mention many just ignore the signal.

[carlsson]

I wonder if auto adjusting to a fixed channel is a problem, i.e. if the signal frequency is not an even multiple of 6 MHz or whatever. Many newer TVs might not fine tune and stick to frequencies inbetween the expected boundaries.

[CatPix]

On 8/7/2019 at 11:07 AM, carlsson said:

As you know, each game contains not only ROM code but also its own CPU, graphics and audio. Most (all?) of them use the uPD777 video game processor which supposedly on its pinout has signals for R-Y, B-Y, Chroma, Video and Sound, possibly even R and G but not B. Assuming this info is reasonably adequate, it should be possible that from inside the console trace the pins for those signals and tap them, just like the built-in circuitry must do to generate the NTSC-J RF signal. However I know nothing about if this is practically doable. I think @slydc has been diving into the Cassette Vision before and may have something to add.

 

https://forums.nesdev.com/viewtopic.php?f=23&t=14568#p176030

I didn't know at all. Interesting. So basically, in fact, the Cassette Vision is just a fancied PC-50x Pong console which use CPU and ROM in the card instead of a Pong chip.

[lazzeri]

On 8/7/2019 at 6:07 AM, carlsson said:

As you know, each game contains not only ROM code but also its own CPU, graphics and audio. Most (all?) of them use the uPD777 video game processor which supposedly on its pinout has signals for R-Y, B-Y, Chroma, Video and Sound, possibly even R and G but not B. Assuming this info is reasonably adequate, it should be possible that from inside the console trace the pins for those signals and tap them, just like the built-in circuitry must do to generate the NTSC-J RF signal. However I know nothing about if this is practically doable. I think @slydc has been diving into the Cassette Vision before and may have something to add.

 

https://forums.nesdev.com/viewtopic.php?f=23&t=14568#p176030

   Apparently the connector pinout is already detailed. You can extract audio (A17) and video (A13) straight from the cart port.

 

   I´m a complete idiot on electronic (and in some other things too 🙂  ) but I guess is not just as simple as soldering a wire over there, probably you must add a small circuit with diodes and resistors and stuff, right?

 

   Might be an easy thing to do?

 

 

[CatPix]

It totally depends on the video levels, if it's too weak you won't get anything, if it's too hight you mgiht have oversaturated video, which might appears like weak video (fuzzy, with low contrast, etc...)

 

Also, "video" here might be black and white video without sync signal, which you'd need to combine with at least A14 and A16, A18 and maybe B1?

 

[carlsson]

Yes, someone in the linked thread tried to tap the signal unmodified but didn't get anything. I believe you would need to amplify it, perhaps follow the RF circuit on the inside to see what it does with the signal. If you're lucky, you only need to build a simple circuit using two (or three) resistors and a transistor, something along this principle which is used on anything from 2600 and upwards.

 

 

The resistances might need to be altered depending on the signal strength, perhaps using a potentiometer for at least one of them.