Sega Master System S-video Mod?

[16-bit]

Hi guys, after doing a successful S-video mod on my Genesis, and I've decided I'd like to give it a try on my Sega Master System model 1.

Does anyone know where I can find a good guide on how to do this?

[omp]

Exactly the same if your genesis is a model 1. Both use CXA1145 video encoders. Later Sega Master System 2's use the MB3514 encoder.

[ApolloBoy]

Early SMSes use a V7040 encoder instead of the CXA1145, but the procedure is pretty much the same, the only real difference being the pin locations.

[Lastcallhall]

Exactly the same if your genesis is a model 1. Both use CXA1145 video encoders. Later Sega Master System 2's use the MB3514 encoder.

Almost true. There are some model ones that use a Sony V7040 video encoder (such as mine). If that's the case, you need to tap pins 13 and 14 - 13 is chroma, and 14 is luma. You can use the same circuit for the CXA1145 to get proper s-video. Looks tremendous, BTW.

EDIT: Ninja'd.

[Guntz]

I've done it too on my CXA1145 SMS, exactly the same method as in the Genesis. The S-Video looks pretty nice to me.

Now if I could just figure out why I can't get Chroma working in my Genesis. Exact same mod as the SMS, but one half of the video isn't working.

[Lastcallhall]

I've done it too on my CXA1145 SMS, exactly the same method as in the Genesis. The S-Video looks pretty nice to me.

Now if I could just figure out why I can't get Chroma working in my Genesis. Exact same mod as the SMS, but one half of the video isn't working.

Try swapping your chroma/luma positions on the s-video jack - I can't tell you how many times I've accidentally swapped them around.

[Guntz]

Except Luma works, so clearly I have them in the right places. My cap is soldered to a pin 2 places to the left of #13, which should be Pin 15, which should be chroma. I even reversed the cap polarity and it still doesn't work.

[Lastcallhall]

What's the resistance value on your chroma line?

[Guntz]

I don't have that particular Genesis in hand at the moment, I'd have to reply later.

Though you gave me an idea. I never tried checking continuity between the capacitor and beyond the S-video jack (like with a cable). Maybe there's something wrong with the jack itself.

[ApolloBoy]

If you placed a capacitor on the chroma line, make sure the positive leg goes to the encoder and the negative goes towards your output.

[16-bit]

Alright guys, thanks for the advice here, I've got a V7040 SMS so now I know which pins to use!

Do I use the same kind of capacitors, resistors, transistors, and whatnot? (I forget what all those things were called, I'm not an electrical engineer and don't solder that often D

[Lastcallhall]

Yes to all. The same circuit used for the CXA1145 can be used on the V7040.

[16-bit]

OH MAN.

I'm so excited to get this started!

I've got one more question here though, what about giving the SMS dual mono audio?

Or a 50hz/60hz switch? Is that a mod that's worth the time?

[Lastcallhall]

OH MAN.

I'm so excited to get this started!

I've got one more question here though, what about giving the SMS dual mono audio?

Sure can - mount two audio jacks and run the audio signal from the AV jack to each one, and ground them. Easy.

Or a 50hz/60hz switch? Is that a mod that's worth the time?

Ive never had a use for one, personally. YMMV.

[16-bit]

I can ground them with the silver looking part on the motherboard right?