What is this? (Mega Drive II Headphone Jack)

http://farm6.static.flickr.com/5174/...38e35a81_b.jpg

It's a part of a CIB Mega Drive II (EU) I'm going to sell. I took it out of the box and on the back is has one of those mini headphone ports. I used a converter to fit a standard pair of headphones and I get the usual static noise upon plugging in my headphones yet I get no sound. I tried with the pack-in Sonic 2 that came with it. Do Mega Drive II's normally have a headphone port like this (or whatever it may be since I can't seem to get sound) or would this be considered modified? I can take a better pic tomorrow. This shitty picture is the only one I have available and the flash was off.

I'm more than certain its put there by someone not Sega.

I was wondering how hard it would be to do this myself on my Model 2. I could tap the right and left channel out of the output jack easy enough but I figure I'd have to build some kinda amp circuit with a volume pot on it to get any reasonable level of sound for an headphone jack.

if I could find a good source of slider pots I will start offering headphone outs for MD2s.

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Originally Posted by TmEE

if I could find a good source of slider pots I will start offering headphone outs for MD2s.

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To be honest I think instead of a volume slider a volume dial like you see on walkmans would fit the style of the Model 2 better.

Though if I put a Headphone jack on a Model 2 I'd put it in the front near the Controller 1 port, so it would be around the same area where it is on the Model 1.

I was more thinking on having the tip of the slider seen near the left side corner, so you can slide slider towards the back and forth. Its even harder to find such dials than sliders, at least locally for me. It would look pretty slick IMO...

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Originally Posted by TmEE

I was more thinking on having the tip of the slider seen near the left side corner, so you can slide slider towards the back and forth. Its even harder to find such dials than sliders, at least locally for me. It would look pretty slick IMO...

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Yeah, with mods like that my goal would be to try and make the system look as stock as possible. So things you put on it look like they belong there and were always there. So people would look that Model 2 with a Headphone jack and go "Wait, did some models have this?"

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Originally Posted by TrekkiesUnite118

Yeah, with mods like that my goal would be to try and make the system look as stock as possible. So things you put on it look like they belong there and were always there. So people would look that Model 2 with a Headphone jack and go "Wait, did some models have this?"

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Just like I did with this particular MD II. :)

Open it up and see how it was done! :D

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Originally Posted by kool kitty89

Open it up and see how it was done! :D

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I'm somewhat hesitating to do that because it's as if it's in NIB condition. Blame it on the virgin tweaks too. If it will help the cause, I suppose I'll do it. I'll have to do it later tonight if not tomorrow.

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Originally Posted by arnold_the_bartender

I'm somewhat hesitating to do that because it's as if it's in NIB condition. Blame it on the virgin tweaks too. If it will help the cause, I suppose I'll do it. I'll have to do it later tonight if not tomorrow.

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Disregard this statement and excuse my being a wuss. If it's modded it would've been opened up already lol. The console looks super new/factory fresh and there isn't a single flaw anywhere so the sleekness fooled me into forgetting that it was modded. The mod looks stock anyways. ;) There isn't a speck of dust even in the tiny crevices of the casing. Anyways, I'll shut up about how this is the newest looking old console I've ever seen and I'm going to report my findings now.

Apparently it doesn't seem like much of a headphone jack mod at all. I would've suspected something to do with the AV out port but in this case it doesn't. There is something very interesting though that I never would've suspected to see. There appears to be some sort of chip added to this particular Mega Drive on top of another chip that came stock with the console. It says the words (from top to bottom) "Sega", "Genesis Mod BD", "Assy . 10-0096REV".

On the bottom of this peculiar chip, there is a series of solder joints labeled J1 through J9 (refer to picture). There are a series of red wires soldered from the strange chip from joints J1, J2, and J9 that are soldered to the chip underneath. There are also red wires soldered from joints J3, J6, J7, and J8 that are soldered to the motherboard on various locations. There is a blue and white wire soldered from said strange chip on J4 and J5 which leads to the supposed headphone jack. Here are some pics.

First of all, here is a better shot of the first pic I took:
http://farm6.static.flickr.com/5297/...907368c6_b.jpg

When I opened it up from the back, I noticed two wires soldered to the headphone jack. On a side note, I also noticed a hole for what would be for the Master System Converter screw just like in the model 1. It even has the metal clip thing. Was this modded as well or did Mega Drives have this feature? Maybe I'm stupid or something because I never recall seeing it on a model 2 Genesis. I'm not much of a model 2 user in the first place.
http://farm6.static.flickr.com/5020/...8029edcf_b.jpg
http://farm6.static.flickr.com/5052/...035a4f59_b.jpg

Here was the "wtf moment" for me:
http://farm5.static.flickr.com/4143/...ffe1ebba_b.jpg

http://farm6.static.flickr.com/5096/...d0ca02c1_b.jpg

http://farm6.static.flickr.com/5015/...d51bec35_b.jpg

I took the liberty of labeling each joint:
http://farm5.static.flickr.com/4123/...7400d632_b.jpg

Finally, a picture of this particularly sexy looking Mega Drive II:
http://farm6.static.flickr.com/5298/...fa01c750_b.jpg

I'd like some input from the experts as to what this mod is supposed to be and what it's supposed to accomplish. Like I said before, I get no sound from the headphone jack though when I power on and power off the console I hear the "thud" noise through my speakers. I was confused so then I did something stupid and used a y-cable and tried to see if maybe it is meant to pass through video. Well, I was wrong. Finally, I tested the console regularly hooked through the AV port and it works perfectly. Video, sound and all. It says Genesis mod on it. Maybe it's supposed to be a region mod?

Wow! Thanks a lot for sharing these! I'm pretty confused tho. Let's see what the experts say.

Are you sure it's a headphone jack? It could be a broken switch or something.

Could be but I there is a contact in there where a headphone plug would hit, plus it fit snugly in the hole and there is no damage visible where a switch would have been. You're probably more right though it makes the "thud" noise when I power the console on and off

Edit: I plugged it in and noticed that the contact gets push away due to the pressure which means it most likely has to be a jack of some kind, headphone or not. The blue and white wires are wired to it as well on the bottom of the jack mechanism.

Interesting, it looks very well done. That might be quite a piece if its factory.

Its wired to the interrupt lines of the processor, but I dunno what's its purpose. Certainly not audio.

Maybe it was for a canceled addon? Kinda like how the slim 360 has a Kinect-dedicated jack. We will never know...

The quality of the installation is fantastic, but there's no way that was a factory job. Nothing like that would be released to the public. It's gotta be some sort of third party mod.

I'm pretty sure it's not audio, but rather a way of either reading or injecting some sort of signal while the console is operating. Perhaps for debugging purposes.

I'm having a hard time reading the markings on the chip. Can you post what it says? Should help pin down what the board does.

The chip is a 74ACT08, I think

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Originally Posted by Jorge Nuno

The chip is a 74ACT08, I think

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You're right about that. I'm just not sure where you got the 78 from. The camera can't capture small details well.

To all who believe it's factory, it's not. It's just doing a damn good job of looking that way sans the wiring job.

Don't sell it until it's identified :)

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Originally Posted by Enternal

Don't sell it until it's identified :)

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Yeah, I'm going to wait until this unknown mod gets identified. Otherwise, I have no use for it. I have a Mega CD II as well to go with it.

Here is the datasheet of that chip, if that helps:
http://www.datasheetcatalog.org/data...onics/4817.pdf

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Originally Posted by Rev!

Here is the datasheet of that chip, if that helps:
http://www.datasheetcatalog.org/data...onics/4817.pdf

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I'm not very good at this so I don't know exactly what to look for. :?

looks to me like some external interrupt source

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Originally Posted by Jax184

The quality of the installation is fantastic, but there's no way that was a factory job. Nothing like that would be released to the public. It's gotta be some sort of third party mod.

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Don't be so certain. Early Sega CD model 2's had a PCB like that with wires going to the main board too.. Later Sega CD model 2's did not have such a thing.

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Originally Posted by TmEE

looks to me like some external interrupt source

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Perhaps a developers unit of some sort?

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Originally Posted by evildragon

Don't be so certain. Early Sega CD model 2's had a PCB like that with wires going to the main board too.. Later Sega CD model 2's did not have such a thing.

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I'm very much familiar with factory repairs, but this very clearly isn't one of those. It all comes down to that jack.

1. It uses a 1/8th stereo jack but isn't for audio. Ordinary people will do what the OP did and plug headphones into it expecting sound. Sega's smarter that.

2. The jack isn't mounted correctly. Not only does it not have a nut on the outside to keep it from being pushed back into the console, but it's also mounted to the top section, so that the lid can't be fully removed without a soldering iron.

3. The jack isn't labeled in any way, nor documented anywhere. In all my years as a hopeless Sega fanboy I've never encountered a reference to that jack.

4. Why would a flaw repair require a connection to the outside world? The purpose of those little boards in certain revisions is to take care of a problem with the design that wasn't discovered until production was already under way.

So I am quite sure this is either third party, or a Sega mod that was only for internal/development use.

Don't forget to quote where I said it could be for development reasons also..

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Originally Posted by Jax184

2. The jack isn't mounted correctly. Not only does it not have a nut on the outside to keep it from being pushed back into the console, but it's also mounted to the top section, so that the lid can't be fully removed without a soldering iron.

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It's secure without a nut. Unless one were to push it in forcefully it would stay put.

I've been trying to google around to see if someone else encountered a Mega Drive like mine but no luck. Something has to hook in that jack.

Alrighty, I'm going to hold onto this Mega Drive (and Mega Cd II) till the end of this month. I need some money. I'm saving up for a motherboard for a computer I've been meaning to build for a long time now. This laptop of mine is getting worn down. Anyone here on Sega-16 who wants to continue investigation can get first dibs (although shipping to Europe cost me 54 bucks last time I sent a box wtf lol) before I list it.

You know after you sell it, we will find that its some rare developer system, anyone with contacts with anyone who worked for sega on the model 2?

Sorry for the thread necromancy, but this is very interesting. Did you ever find out just what this was?

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Originally Posted by Growl

Sorry for the thread necromancy, but this is very interesting. Did you ever find out just what this was?

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Nope. I still don't know what it is. Just noticed your post out of curiosity which is why I replied late.

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Originally Posted by arnold_the_bartender

Nope. I still don't know what it is. Just noticed your post out of curiosity which is why I replied late.

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Did you wind up selling the system already, or is it just sitting around still?

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Originally Posted by xelement5x

Did you wind up selling the system already, or is it just sitting around still?

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Still sitting in the game room in the box. I'll only sell it to someone who's interested (and is an expert in this) in the sake of the mod, otherwise I'm keeping it.