Adding RGB to a brazilian Master System results in dark picture or how to amp sync?

Hey there,

I decided to open a thread to ask that since I'm having just small conversations with a bunch of people and it would be great if more could help out.

The brazilian master system uses the MC1377P video encoder.

I'm getting R G B from the Sega chip itself before going to the encoder.
The sync I'm getting from the composite output.

The result is a perfect but darker picture.

The image was way darker before I added a caps of 220uF to the sync line.
The 75 Ohm +220uF on the R G B line just gave me a little bit cleaner picture but not much.

I'm using a cable I build myself from a VGA cable which has R G B individually shielded.

So I believe the problem lies on the sync line. So how can I amp the sync?
A higher caps like 400uF would work?

 

The dark picture problem comes from the fact that you have no amplifier on your circuit.

On a "decent" (non Tec Toy) SMS or on a SMS2 you have a CXA1145 where you can tap amplified RGB signal from. MC1377 is a piece of trash chip from 1975 which Tec Toy used only to save a few bucks on each unit they produced. To get a decent image from the MC1377 you need a bucket load of analog parts. And the Tec Toy SMS skimps on a lot of the required parts, again for costs reduction.

 

Im having the same problem with a s-video mod. Any help?

 

Get an american powerbase sega master system on ebay.

They go for $20 and you will have much less trouble.
Tectoy it's not worth it.