Bare with me, I'm new to electronics work in general. And this is my first post.

I'm working on an NES mod. I bought an NES on eBay and it came with this weird AC adapter. It has two cords coming out of it. A little research, and I discovered that it works with the Genesis and NES/SNES.

I took it apart (and I've never looked at the insides of one of these before) and found this:

http://i.imgur.com/FdQ1s.jpg

Why is such a little circuit board mounted in such a big space? Is it because it gets really hot (it also has a "vent" on the back of the casing). I ask this because I want to mount the AC adapter into my case mod. And I don't want it catching on fire. D:

And what's with the messy adhesive? It looks like strands of it are all over the component. Is that epoxy (it's yellow and purple, if that means anything)? And if so, how do I remove it?

Sorry for the rapid fire questions. Thanks in advance, everyone.

What an awfully small power rating...only 350 mA? That's not quite enough to power a NES properly....You might want to pick up a different 9v AC adapter. One that can supply at least 800 mA.

Although, if it does work don't worry about it getting too hot since it's hardly moving any current. The reason for such a large case is most likely because it's just a stock case. As for the glue, that's not a problem either, it' just there to keep things from rattling around, nothing important with the color of the glue. Just cut at it with something and try not to cut any board parts and you'll be fine.

I didn't notice that power rating inside of there... that's odd. The back of the case says it's 850mA. I checked to see if the 3 is really a worn out 8, but it's definitely a 3. It must just be a typo, because I tried powering the system with it and it works fine.

It's a newer (cheaper) designed AC adapter, probably bought by the person selling the NES on ebay because they were cheap and look brand new.

The reason power bricks were always so big is that they used to have a decent sized transformer in them to drop the voltage, and maybe some filtering capacitors.

What you have there is a pretty simple and cheap switching regulator. It eliminates the need for a big more expensive transformer in exchange for a handful of passive components.

If you were to throw it on a scope and look at the power quality you might see it's pretty noisy, but the NES has some filtering inside itself so it's not a big deal.

Same principle as most phone chargers.

If it needed to cool it would probably be bolted to a heatsink. I think it's huge to make people think it's like an official one

Be very careful with these cheap 9V transformers!
I had 3 : -First started fizziling when i plugged it in
-second one was outputting 13V and then it dropped to 0V
-the third just melted and almost caught fire!
They are a real danger to you and your home!