MCD Sega Multimega Black Screen

[Alaziel]

hello,

I have in my possession for more than 10 years a sega Multimega .
but the console no longer works.
the problems are as follows.

- in cartridge mode ( black screen after the TMSS screen) small accuracy the TMSS does not display all the time at startup.

-in CD mode simply no display (no bios) the CD turns 2/3s when the machine is switched on and off.

-signal detected on TV exclude MB3514 video encoder?
-all tracks checked around IC1, IC9,IC5,IC14.

-Audio CD mode works without sound problems via headphone output and playback ok

 

[nitelich]

Have the console's capacitors been replaced? Any other modwork been done? Can you open the console and show a pic of its PCB?

I don't know about the CDX/MultiMega specifically, but I have a few Genesis variants whose caps went bad. I know the 1st model Sega CD is prone to capacitor-related failures.

 

[Alaziel]

Have the console's capacitors been replaced? Any other modwork been done? Can you open the console and show a pic of its PCB?

I don't know about the CDX/MultiMega specifically, but I have a few Genesis variants whose caps went bad. I know the 1st model Sega CD is prone to capacitor-related failures.

Hello

Yes all capacitors are replaced for the MD board.
no mods.
The only thing I didn’t check all the voltages on the power board.
I saw a video recently where the oscillator might be involved ( no image)

 

[Alaziel]

 

[Alaziel]

 

[nitelich]

Yeah, the caps and the coin cell battery both look great. There is one leg of X2 that doesn't look soldered down (at least on the side pictured; could very well be soldered on the back side since its thru-hole), but I am not super-familiar with CDX/MultiMega compared to standard Sega CD models.

There is a fairly lengthy thread of Sega CD and all-in-one unit debugging over on Sega-16. This page specifically talks about one CDX debugging that is vaguely close to your issue. That thread is still pretty active to this day, so you might want to cross-post there if no one else here has ideas.