Regionmodding a genesis 2

[Skoldis]

This is the cable i am using:
Attachment 9574

Thanks for the tip Helder!

[Skoldis]

i talked to my friend who own the pal mdII i regionmodded, apparently his also displays 50 hz in b&w.
This was a pal mdII from the beginning so i really don't understand this. I can admit that i actually don't know much about the
electronics, i always just follow guides i find online, i am however good at soldering when i know what i'm supposed to do :P

[Helder]

If you don't want to buy a board from the guy I linked to he seems like a nice guy and will probably tell you how to wire up the 2 oscillators on some perf board and you can add it to the switches you have now.

[omp]

If you are using scart rgb cable it should be ok. Maybe your tv has an scart connection but is composite only?

[cleeg]

^ Could be right, SCART sockets are non standard animals, rather annonyingly. Try a different socket or TV. Some are labelled RBG even.

[Skoldis]

i did try with different tvs and sockets. i tried to connected it directly to the rgb slot, through a scartconverter & i even tried soldering a separate rca port, but it is still always b&w. I made the mod by soldering the cables at the jp points.

@Helder I tried to register at assemblergames but whatever username i choose it says its already taken :P (i even tried with gibberish)

[Helder]

I can ask him for a schematic and see if he will provide one and you can adopt the design with the switches.

[Skoldis]

that would be really nice! thanks!

[Helder]

He joined the forums and is awaiting admin approval of his account and he will post schematics of his work.

[Skoldis]

That's awesome! thanks!

[The Real Phoenix]

Hi there! So Helder told me to come check-up this thread.
First of all, I'm not a natural English speaker, so I excuse me for all the mistakes I'll wrote.
Also, my board is kinda in work in progress.

So I made a board for the Genesis 2 which auto switch to PAL or NTSC Color Crystal subcarrier. It's an adaptation of a similar board I designed for the Genesis 1, but with automatic function (the other use a switch to allow forcing signals)
Here's the scematic:


Here's a exemple of a board. I'm not happy of the current design, but at least it corrects the flaws of my earlier prototype


- You need: Ground, +5v, Video signal (named as MB7), Original Crystal signal (named as MB6) , feed to the video chip (named as PIN6). I found a great place at R61 and removing it (my board includes the R61 as the 10k resistor)
- It analyses the signal incoming to pin 7 of the video chip (or from the JP3/4, it's the same signal), compare to another logic (Low or High) and a 74HC052 will "open" one or another circuit with the proper Crystal:

• if identical, uses original crystal signal
• if not, then if ground uses PAL
• if not, then uses NTSC

- Since the Genesis 2 doesn't have a Crystal Driver, and 2 pins Crystal are more easy to find than 4 pins (especially 4.43Mhz ones) I had to use a 74HC04 as a driver.
- It works fine with my switchless board, but since it's based on the NTSC/PAL logic on pin 7 it could easily fit with your switch mod.

Tested with two Genesis 2 VA1.8, one with a Fujitsu MB3514 and the other with a Samsung KA2195D. I've order two Sony CXA1145m to have a decent output and made some Svideo mode .

Here's some pics of the installation:



Note that it works perfectly with the KA2195D, but the MB3514 doesn't like "on-the-fly" change, but works fine on cool boot.

[The Real Phoenix]

Hi, I'm the dude that Helder is talking about. I made a long post 3 days ago, but it seems the moderator didn't approve it (yet?).
I'll wait a bit longer but I'll eventually re-post the whole thing.

[Skoldis]

Thanks for that! i don't know how this forum works with that

[The Real Phoenix]

Post is up. Thanks admin/moderator.

[Helder]

Once you have a solid design you should sell these as I'm sure they will sell well.

Just wondering if you really need that variable capacitor at the bottom or can 30pf be used in it's place?