JVC X'Eye Sound Issue (Know Your Genesis Model 2? Get In Here!)

[InsaneDavid]

Alright, a quick query for advice before I go into recovery mode and part out this console.

I have a reported non-working JVC X'Eye I picked up in a trade and aside from some obvious physical repairs (that have no bearing on the issue) that need to be done, there's a technical problem I could use some help with.

This all has to do with the Genesis side of the X'Eye, in other words with cartridge games.

All games start up fine but there is missing audio across the board. It's been a long time since I've looked into how audio chips work but from what I remember and understood, audio hardware can reproduce a set number of audio channels. I think that the problem is certain channels are not being outputted or given anything to output.

A couple of games I've tried are Sonic 1 and Super Monaco GP. In Sonic 1 the game is missing the "SEGA" into sound effect and it sounds like some of the auxiliary sound effects (beat leading into the title theme) are missing. Aside from that the other audio seems okay and the game plays fine. In Super Monaco GP I get absolutely no sound but I think that game uses a single audio channel anyway. Since there's normally no voice sounds over sound effects, no music during gameplay, etc.

The part below is an idiot attempting to make an EXAMPLE...

The way I understand it there are so many voices or channels or whatever that a sound chip can produce. For the sake of making it easy, let's say the Genesis has 4 channels. This lets you layer audio so the music doesn't have to stop when you have a sound effect or whatever. Again, I'm just making this up as an example but for instance...

Sonic 1:
Channel 1: Used for voice and background enhancement.
Channel 2: Music.
Channel 3: Sound effects.
Channel 4: Not used.

So for instance, if channel 1 wasn't outputting properly you wouldn't get the "SEGA" sound or the beat that leads into the theme music. You will also be missing any other helper sounds that may be sent on that channel but they might not be as apparent. They may be just a couple notes here and there or an extra reverberation effect on an item pick up, etc. Everything else would be fine though. Now another example...

Super Monaco GP:
Channel 1: Used for everything.
Channel 2: Not used.
Channel 3: Not used.
Channel 4: Not used.

In this case, if channel 1 was bad you wouldn't hear anything. I think this is the case since when a voice sample plays in this game the sound effects cut out. Additionally music and sound effects cannot be played at the same time.

Idiot not knowing what he's talking about and attempting to sort it out in his head ends here.

I've had the same results with using both RCA cables and the Genesis 2 multi out cable. Cart slot is pristine, cartridges are clean, and the PCB is spotless with no cracked solder joints, blown components or any other evidence of component failure.

Any help would be great, thanks!

[FABombjoy]

PSG failure, perhaps?

If the FM sounds are there, I'd start by digging up the PSG pick-up point for the Genesis Crystal Clear Audio Mod & check for signal.

[InsaneDavid]

Thanks FABombjoy, I'll take a look at the schematic for the mod and trace it back.

The more I mess around with it the more I realize that the whole board is getting damn hot. Also from a cold start I don't get the X'Eye splash screen, instead it's just an orange or gray solid screen. Boot to a cartridge and then try to power up without a cartridge and I'll get the splash screen. Coupled with how the CD drive has broken plastic standoffs and missing screws, I'd say this has been monkeyed with quite a bit before it was put into my hands.

It's looking like I'm going to trade the main PCB for a couple Dreamcast power boards (something I actually need ) and put the rest in the parts bin.