Modded SuperGrafx + Super cd-rom2 audio question

[Stimja]

Hey Guys,
First time poster, so please let me know if I'm doing anything wrong.  I've searched on this topic a few times and gotten related hits, but nothing specifically like mine.
I've got a modded Supergrafx (modded with a region switch and a scart rgb out) from a ebay seller doujindance.
I bought an additional Super cd-rom2 to mount onto it.  The super cd-rom2 unit has bad caps.  I haven't opened it, but I knew this because the original seller said audio out didn't work, and that symptom matches a number of these units having bad caps (similar to duos).
I expected to have to get this repaired upon receiving the cd-rom2.  Before sending it out for repair, I hooked up the drive and tested it to make sure everything else was okay.  I played several games (Dracula X, Y's 1 and 2, Y's IV and Valis 2).  As long as I hook the audio to the Supergrafx out, and don't plug anything into the Super cd-rom2 out, I get cd sound through the Supergrafx.
This brings up 2 questions:
1) Has anyone else seen similar behavior?  My earlier searches were here before buying the Super cd-rom2 (as a forum lurker).  Based on what I read then, this shouldn't be working this way.  I should only be getting sound effects and digitized sound.  I do remember seeing a guide previously that stated that the cd audio was handed back to the console over a few pins, but the console didn't use it.  So I guess it is possible the original modder (doujindance) hooked that to the av-out while doing the RGB mod.
2) Is there any reason to get the bad caps in the super cd-rom2 fixed, other than selling it?
If this is a result of a mod, it seems like it would be smarter to do something similar, rather than hacking up a ~$200 Super cd-rom2 if you had the same problem (not that replacing caps is hard for a experienced solderer).  I know I have a Supergrafx, which isn't cheap, but if you didn't want that compatibility, cores and pc engine small units are really inexpensive, and not a lot lost if you mess up the mod bigtime.

[Necromancer]

Welcome aboard!  I don't have such hardware so I can't speak to how they should/shouldn't be able to operate, but you should change the caps.  If they've failed they've leaked on the board, which can and will eventually cause other problems (corrosion of components, short circuits, digital AIDS, etc.).

P.S. - There is no apostrophe in Ys.  

[soop]

Howdy, howdy.  Nah, there's no real reason to get the caps replaced if you don't mind re-routing the sound, I think by the time something else goes wrong, you'll be able to replace them if necessary without permanent harm. [note, I'm certainly not the most qualified person to be talking to on this forum]

However, I will say firstly, that the mod using pin-outs should not impede the transfer of audio, and secondly, I was under the impression that Super CD ROM2s are among the more robust units.

And lastly, while you can play anything with that set-up and a system 1 and arcade card, I don't like the fact that they both need power.  It's just a small thing, but I currently have one (universal) PSU that fits both, so I have a Core II in my SCD and my Super Grafx separate on the floor.  Then I use which ever one until I want to play something that requires me to swap.

[BlueBMW]

Personally Id recommend having the caps replaced.  As was said they will eventually damage something that is critical to system operation.  Super CDroms seem to be just as prone to cap problems as the original duos.  They're just newer so we are only just now starting to see problems.

[soop]

Ooops - disregard what I said then.  Blue is much better than me at this.

[vestcoat]

1) Has anyone else seen similar behavior?  My earlier searches were here before buying the Super cd-rom2 (as a forum lurker).  Based on what I read then, this shouldn't be working this way.  I should only be getting sound effects and digitized sound.  

I have the same setup, unmodded, and all of the sound works from either output.  When I hooked it up I was unsure which to use and played off the SGX AV out for years.  Recently, I noticed that using the SGX out boosts the sound effects a little too much and that they were drowning out the redbook audio on Cotton, so I switched it.  Of course, maybe this is because the caps in the SCD are starting to go bad.   Edit:  althought the SCD is a little quieter, the PSG-to-Redbook mix is even.  This topic may be of interest:  http://www.pcenginefx.com/forums/index.php?topic=8152.0

[Bonknuts]

There's mono audio input on the back plane (same as the hucard audio in pin). This gets mixed and output on the core system itself, but it won't be stereo. IIRC, the SGX isn't any different (i.e. the input is still mono on the back plane). So while it works, the PSG will be stereo and such but the CD audio through that port won't be. So if the caps aren't bad, use the SCD audio output jack instead of the SGX one.

[Stimja]

Thanks for the info.  This now makes more sense to me. 
Also, I'm not using two power adapters.  I have a cable that strings the power from the SCD to the SGX.

[Bonknuts]

Also, I'm not using two power adapters.  I have a cable that strings the power from the SCD to the SGX.

 Same here. I have a pass through power connector for the PCE and one for the SGX.

[soop]

Thanks for the info.  This now makes more sense to me. 
Also, I'm not using two power adapters.  I have a cable that strings the power from the SCD to the SGX.

A

Also, I'm not using two power adapters.  I have a cable that strings the power from the SCD to the SGX.

 Same here. I have a pass through power connector for the PCE and one for the SGX.

Huh, didn't know such a thing existed!

[vestcoat]

Also, I'm not using two power adapters.  I have a cable that strings the power from the SCD to the SGX.

 Same here. I have a pass through power connector for the PCE and one for the SGX.

Dang.  Did the SCD originally come with both?  I only got the one for PCE.

[Stimja]

I didn't get either with the drive(used auction drive), but I ordered them from game doctor hk.  It was about 8 bucks.

[Bonknuts]

I got mine used and without a box/complete. It only came with the PCE one, so I made an SGX one. Never seen a real SGX pass-through one though.