Genesis 2 region & 50/60Hz modification?

[RM2]

This Genesis 2 has a different board revision, and a different 208 pin chip, than either what's discussed on GameSX or Mike G's page.

The instructions given both places are not helpful here as pin 107 on this particular chip is the red video signal so it's obviously not the pin of interest.

I sent the following info to Mark Knibbs but he suggested I ask here. I suppose the only way to solve this is to hope someone has a Japan and/or PAL Megadrive 2 with the same chip who can test the pins and see which are different than what I measured below.

It's a US Model MK-1631A, made in Thailand. Board marking reads "PC BD MD2 VA2.3 USA"

The layout is similar to the PAL VA1 board Mike G shows here:
http://www.mikeg2.freeserve.co.uk/masterful/md2lang.html
...but it's not identical. The Z80 is on the lower left, the 68000 is about where the Z80 was, and some other stuff is moved around too.

Of most importance though is the big custom 208-pin chip is labeled
315-5685
TC6158AF
JAPAN 9411EAI

It's rotated 90 degrees clockwise compared to the picture above and as already mentioned does not have the same pinout as the 315-5660 on the board on that page, as pin 107 is the red video signal here. Unlike VA4, there's no obvious zerohm jumpers either and it's clearly not like that chip since the system still has a separate Z80 and Yamaha sound chip.

Via continuity test and the video encoder pinout (a Samsung chip on this particular system) I've figured out the following:
Pin 10 - 5V
38 - gnd
43 - 5V
60 - gnd
61 - 5V
96 - gnd
97 - 5V
105 - 5V
106 - 5V
107 - red video
108 - green video
109 - blue video
110 - gnd
142 - gnd
147 - 5V
153 - 5V
154 - 5V
156 - 5V
158 - 5V
160 - gnd
164 - gnd
165 - 5V
204 - gnd
205 - 5V
208 - 5V


May I suggest an update to the GameSX page's reference to 315-XXXX chips since they don't all have the same pinout as that page suggests they do? Someone using those instructions to modify a system with this board/chip revision will be cutting traces they shouldn't be and certainly won't attain the desired result.

[pr3ston]

Hy,

i had the same Board and still noch slution for a mod on this baby  
Do you have found out something in the meantime ?