Sega CDX Blank LCD screen

Started by Silver52, January 31, 2021, 05:18:39 AM

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I don't think it's anything too serious as the console still run just fine with both
genesis and Sega cd games, but it's a bit concerning.

The LCD display lights up but it either show up blank or the numbers are partly missing. Sometimes it ends up working after a long period of play.
Though the display will go back blank after it is turned off.

Is there's a solution for this?


If I recall correctly, this is a problem with the tolerances inside the CDX/MultiMega unit being really crazy tight and unforgiving. The smart money bet is that there's nothing wrong with the LCD display itself, since you haven't mentioned anything about the black display liquid pooling or being persistent in the display when the CDX is powered off. So if you're brave enough to fix it, this is something that might be resolved with some connector maintenance. That means reseating a ribbon cable at both ends in the best case scenario, or in the worst case having to desolder and remount the cable mounts at the PCB end.


That's correct.
No liquid pooling on the display anywhere. I sometime see a low battery icon shows up which itself is strange since I never put any batteries in the system.

As for reseating the ribbon cable, you mean the ribbon cable that connects the CD rom to the PCB?


Stealing an image from Reddit for illustration purposes:

The little display sits on a white plastic wedge thing, and now that I'm actually looking at it again I realize I'm probably mistaken, in that there's just friction contact connection there and no ribbon between the LCD and the CD-ROM board. Maybe those contacts below just need a good cleaning?


It's possible the contacts could use some cleaning. I'll have to look inside of it to be sure.

My theory is that the display is fine, just as you said earlier, just there's no power or not enough power going into it.

I have heard that the capacitors in the Sega CDX could be the problem and people like to change them all out, but I have yet to see it be the solution to fixed anything in the console. (At least from the videos online I seen)


About the capacitors in the CDX? That very last round of Genesis/Megadrive hardware seem to fall outside of the timeframe for the crappy electrolytic capacitors that seem to have plagued the 8-bit and 16-bit hardware of the time. However, absent hard information about what batches were bad and which components were used, there's no way to be sure. Also, the CDX is much, much harder to recap than other comparable systems of the time just because so many parts are crammed onto those tiny PCBs. It's also not unlikely that one or more of the caps on those boards are smaller tantalum capacitors, rather than the traditional aluminum-with-gooey-electrolyte type that most others are.

This is by way of saying that I agree with you that recapping the CDX isn't the first thing you should be looking into. It's certainly not a job I'd like to try.