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MD [Solved] Problem with SEBs code switching frequencies and sega genesis model 2


New member
Original poster
Jul 24, 2019
Hi Everyone,

I just started working on modifying my Sega Gensis 2 (PC BD MD2 VA1 USA).
I have a pic 16f630 loaded up with SEBs code from his github repository. I've soldered everything into the genesis and powered it up.
Holding the button for longer than one second switches the LED colours between red green and orange, and the voltages for the language code switch between 0 volts and 5 volts respectively. However my problem is with the 50hz/60hz. When I press the reset button to switch the frequencies, the LED will only ever flash 3 times indicating 60hz. I am unable to switch to 50hz at all. This seems to be problematic as I cant start a european PAL game (clay fighter) on my genesis. Im not sure what's wrong there. No matter how long I change my presses, the PIC seems to be stuck outputting 60hz. Can anyone give me any advice there? I want to stick with SEBs code, because I want to use the multibios for the sega cd next.

Thanks for any help!

*Edited, had wrong PCB verison written down

Edit 2: Hey Guy, I solved it with a good nights sleep.

For anyone else that has the same problem as me, there is a difference between the PAL and Gensis PCB setup.
mmonkey and Wolfsoft show that PAL PCBs have the ground attached to leg 46, but on Genesis consoles, VSS is tied to leg 46. So you need to cut the VSS connection to leg 46 in order to be able to switch between 50 and 60hz. After I cut that trace, everything works perfectly! Now its time to do the multibios mod
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