Colecovision S-Video Mod kit

[the_crayon_king]

So I know I made one of this before but no idea where it is.

Link: https://easyeda.com/hotdog6394/Coleco_S_Video_THS7316_Simple-b548a71e066149238e6273ff2cdfa928

 

Probably the board Ill be using from now on.

This is all SMD stuff but I think its easier than the LM318 method.

Should be small enough to fit between that mess of caps and chip next to the RF pad.

Will likely be one of many "simple" boards for various consoles.

Tested on my crappy CRT and also with an XRGB.

 

Ill have pics of install in a few months (sorry I am moving).

Pics of schematics/board:

 

The two resistors are TBD but are just apart of a voltage divider since the coleco already puts out 1.4V? luma. Just use 2x 1k resistors

 

 

 

[Osgeld]

single sided surface mount is what I would do (and do on a similar setup for my generic composite video driver using more or less the same chip)

 

reason I say that is anyone can grab gerbers or even a to scale PDF and etch a board and pretty much be done vs drilling a load of holes and blah blah blah, or heck hand draw it with a sharpie. And once one gets used to SMT its much faster to solder, even with an iron (as long as people dont go smaller than 0805 parts)

 

personal note, not that my entire post to this point has not been opinion heh, but I almost always omit the 75 ohm resistors on the output

[the_crayon_king]

single sided surface mount is what I would do (and do on a similar setup for my generic composite video driver using more or less the same chip)

 

reason I say that is anyone can grab gerbers or even a to scale PDF and etch a board and pretty much be done vs drilling a load of holes and blah blah blah, or heck hand draw it with a sharpie. And once one gets used to SMT its much faster to solder, even with an iron (as long as people dont go smaller than 0805 parts)

 

personal note, not that my entire post to this point has not been opinion heh, but I almost always omit the 75 ohm resistors on the output

 

This board IS one sided SMD, the other side is finished but not a ground plane.

All components are 0805 except for the 220uf cap which is 1411

 

The 75 ohms are there to divide the output and impedance match.

Will it work without them and/or the caps there ? Probably. But I dunno if that's "best practice"

 

I don't typically design through hole stuff. You are correct that you could use a generic THS731X board that could be adjusted to anything. I forgot about it but I was going to make THS7374 boards to do everything.

This info is more for posterity in case anyone wants to try with SOIC/SMD sized parts.

 

There is a sister board that goes with this:

https://easyeda.com/hotdog6394/MD_40SV-1de03b6b5f054f4e87a9acbcaf2880c9

It's to break out S-Video into MD-40SV

 

I am at a loss trying to figure out the jailbars though as they appear independent of a mod. They seem to be tied to the VRAM or R0-R7 of the ppu. I do wonder if anyone has had any luck removing them.