Finding Subcarrier Trace on Model 2 Genesis VA4 [Majesco]

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tanknat007
Posts: 2
Joined: Sun May 24, 2020 2:36 pm

Finding Subcarrier Trace on Model 2 Genesis VA4 [Majesco]

Post by tanknat007 »

Hello, everybody. As many other Sega Genesis consoles have, my Majesco Model 2 VA4 has jailbars. I read this thread [viewtopic.php?f=6&t=60696&start=90] and saw that a few users were able to cut the subcarrier trace near the 315-5960 and rid of their jailbars successfully, and I want to do the same, having had success with cutting a trace on a Model 1 VA3 Genesis. Losing the Composite signal is of no concern to me, since I use HD Retrovision cables in my setup.

For quite a while, I've searched high and low around the web with no luck finding a specific diagram of pinouts or a photo showing the subcarrier trace on the Majesco Genesis Model 2 VA4, and I'd really like some guidance with this task or at least photos that could help me with locating the trace and where I could cut it. Following the trace from pin 6 of the Sony CXA1645M encoder to the Sega 315-5960 has been very difficult for me to figure out.

Thank you all for any help that you can give me!
Ruprit
Posts: 58
Joined: Sun Sep 02, 2012 4:50 pm

Re: Finding Subcarrier Trace on Model 2 Genesis VA4 [Majesco

Post by Ruprit »

Sure thing.

Credit goes to Unmaker64 who helped me with the same issue.

You will want to lift SCBR pin 153 on the 315-5960 ASIC.

Along with a Triple Bypass install got rid of the jailbars.

https://abload.de/img/315-5960_asicomkup.jpg

https://abload.de/img/img_20200305_16550424zek8x.jpg

If I recall, you can also start at Pin 6 of the CXA1645 to trace back to SCBR.
tanknat007
Posts: 2
Joined: Sun May 24, 2020 2:36 pm

Re: Finding Subcarrier Trace on Model 2 Genesis VA4 [Majesco

Post by tanknat007 »

You have ended over a year of searches, Ruprit! I already performed the pin lift and the jailbars are gone! Thank you so much for posting Unmaker64's work!
Ruprit
Posts: 58
Joined: Sun Sep 02, 2012 4:50 pm

Re: Finding Subcarrier Trace on Model 2 Genesis VA4 [Majesco

Post by Ruprit »

That's awesome! Happy to help.
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