This instructable will go through the steps to make an NES act like it was new.
Old consoles tend to have some issues, but most commonly, these can be resolved by simply cleaning the contacts and inside of the casing.
I will be posting restoration projects for several retro systems and accessories over the next few days, they are very similar projects because they function the same way.
Step 1: Opening the Case
On the bottom of the console, there are 6 Philips screws. Remove them with the screwdriver, and then remove the entire top half of the console.
The top half has no electronics, and usually just needs a good wipe-down.
The bottom half of the console is where all of the electronic lie.
First, remove the metal shield by taking out all of the screws and sliding the shield out.
Next, remove all other screws that you can see, and put them aside. Note that the screws circled in white are a different size.
You can now slide out the cartridge holder, and remove the motherboard.
Unclip the wiring harnesses, and everything should come apart pretty easily at this point.
Use the rubbing alcohol to clean every little part. The slot that holds the cartridges in place can be cleaned with a credit card that has a microfiber cloth on it which is soaked in alcohol.
You can see on the zoomed in pix how much gunk accumulates in the vents.
Tip- a very common problem that people have is that the games do not stay "down" or clicked in place when using the NES for awhile. This is an easy fix. The problem is that usually the screws are too tight. Loosen the 2 screws at the very front of the cartridge holder (circled in red) a bit and that should solve the problem. If it persists, loosen the screw on the bottom of the console which is located in the center toward the front. That should do the trick.
When you are done, simply put everything back in reverse order.
This machine is overall a simple tear-down so far as Nintendo systems go, because there is a lot of extra space.