32x Problems

[NeWmAn]

Hello,
I have 2 non working 32x, both have the same problem: The video mixer (315-5788) is not working.

The symptoms  are these:
MD and 32x connected with video link cable --> On the 32x A/V Out I get only the 32x generated video.
If I connect the video cable to the MD I am able to see the missing parts of the image (background or sprites), so the MD video fine.

Is this a common problem? Does someone have fix for it?
Thanks.

Update:
Now one of the 2 doesn't want to work anymore, it only displays the TMSS notice 

[kendrick]

It's been my experience that most 32x problems are related to cartridge port contact issues. If all you get the TMSS message, that tells me that your Genesis/Megadrive unit doesn't detect the device at all. It's very unlikely that both 32x units have failed in exactly the same way, so in your shoes my next step would be to find a known-good working Genesis and try running each 32x on it to see if the result is still the same.

[l_oliveira]

There's a pin on the cartridge slot that signals the 32X when the MD/Genesis VDP chip is generating the "transparent" color.
That signal is named "Y/S". I'd suggest you look for the "Tec Toy" schematics for VA3-USA (Genesis) motherboard.
It's the 4 pages schematic that has been floating the interwebs for a few years now.

Honestly it's possible that your console is at fault. Check the 32X units on other console.

[NeWmAn]

Problem solved, it was the console. 
Thanks to both of you for your help!

I'd suggest you look for the "Tec Toy" schematics for VA3-USA (Genesis) motherboard. 

I'm unable to find this, can you tell me where to find it?
Thanks.

[l_oliveira]

http://emu-docs.org/?page=All%20Consoles

http://emu-docs.org/Genesis/mega1.png  (1st half of schematics)
http://emu-docs.org/Genesis/mega2.png  (2nd half of schematics)
http://emu-docs.org/Genesis/mega3.png  (block diagram)

It's the files I meant but they're three instead of four...