Hi Planet VB!

I recently decided to attempt the solder fix. It went great for LED 2 but LED 1 is exhibiting horizontal lines and glitchy screens.

I know that both motherboard sockets are fine since LED 2 works on either side without issue. LED 1 shows the same problems on both sides. Strangely, both LEDs have issues when they are both plugged in.

I did lots of testing with my multimeter and found a bridge between the leads boxed in the picture. I cleaned out the space between them and the bridge went away. The LED was still problematic, so I tested the leads and they were bridged again! I can’t explain this phenomenon and I don’t know how to proceed.

What causes a bridge to occur when the system is turned on? What should my next course of action be?

All the best

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Hi Scotty, welcome to the forum!

>>Strangely, both LEDs have issues when they are both plugged in.>> it may seem strange, but they actually share a lot of pins on the data bus (they both have matching shift registers). So this is common behavior if one is faulty.

Are you sure you measured the right spot? There is supposed to be a bridge when you move that red box one pin over. But not where it currently is.

>>What causes a bridge to occur when the system is turned on? >>
floating data bus, intermittent connection, crappy 25 year old melted ribbon cable… 😉

>>What should my next course of action be?>>
Maybe buy a Virtual Ribbon? 😛
https://segasonicfan.wixsite.com/retro/virtual-ribbon

Thanks for the detailed reply!

I’m glad that the behavior with both plugged in is expected. That helps to narrow down the problem.
I know which leads you are talking about that are supposed to be bridged. I triple checked to make sure I was not mistaking them.
The only other thing that could be causing an issue is a bridge occuring in the via (layered PCB) and that could be problematic.
In any case I will be checking out virtual ribbon