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How To Overclock the NES

July 28, 2014

There are a ton of NES games that have annoying slowdown when there are too many things happening at once. One way to get rid of slowdown (or greatly reduce it) is to overclock your NES.

Things you need to know before attempting this:

This will not fix blinking sprites. Sprite blinking was programmed in many games to allow more sprites to seemingly be on the screen at the same time.

This will not work properly with all games. I strongly recommend installing a switch so you can switch between normal and overclocked mode. I am writing this guide with the switch included.

This will make the sound higher pitched. Most people won’t realize the pitch has been raised unless you are actually trying to compare the two.

This guide is for the front loader (Toaster) NES.

NTSC and PAL systems have different clock speeds. Both can be overclocked.

Things needed:

  • Oscillator: For NTSC systems a 24 MHz or 26 MHz oscillator would be best. I don’t recommend going higher than 28 MHz. Most of the slowdown I noticed had been fixed, or greatly improved, at around 24 MHz. For PAL systems I would stay in the range of 32 MHz to 38 MHz. This is all personal preference. I prefer lower overclock speeds as I only want to reduce slowdown, not play games extremely fast.
  • (Optional) RGB LED: If you want to have the LED on the front of the NES turn blue or green when overclocked and red when normal then get this.
  • Switch: If you decide to use the RGB LED, you will need a double pole double throw (DPDT) switch. Otherwise you will only need a single pole double throw (SPDT) switch.
  • Drill and drill bits to drill the hole for the switch.
  • Solid 30 AWG wire for the clock signals.
  • Stranded wire for power and LED upgrade.
  • Hot glue gun to mount the oscillator

Step 1 – Drill the hole for the switch

Once you have your Nintendo apart, you should decide where you want the switch and drill a hole for it. The easiest place to drill would be on the back somewhere. I drilled underneath the NES so the switch would be somewhat hidden (it is a tricky spot to drill). Wherever you decide you want the switch, make sure it has enough clearance from the board and other parts of the case. Don’t install the switch yet – just make sure it fits properly.

NES Overclock

Step 2 – Cut the master clock trace

Now you need to find this trace on your board and cut it. I cut it in two places and did a continuity check to make sure it was completely cut. Make sure you don’t cut the wrong trace on accident. The picture is of an NTSC RP2A03G CPU. PAL Systems will have a RP2A07G CPU.

NES Overclock

Step 3 – Wire up the oscillator

  • Pin 1 – N/A
  • Pin 2 – Ground on Voltage Regulator
  • Pin 3 – Clock signal (to switch, see drawing below)
  • Pin 4 – +5 VDC from Voltage Regulator

Here is the voltage regulator:

NES Overclock Voltage Regulator

Solder the +5VDC (red wire) and Ground (green wire) here.

NES Overclock Voltage Regulator Solder Points

Step 4 – Hook up the switch to the clocks

PAL systems have a RP2A07G CPU and a RP2C07-0 PPU. The pins are the same.

NES Overclock Mod With Switch Schematics

In the picture below, I took the original clock from the other side of the trace that was cut instead of pin 18 of the PPU. Either way is good.

NES Overclock Mod Installation

Once you have everything hooked up properly, test out both the original clock and the new clock signals. You will have to turn the system off to switch between the two clocks.

If one or both of the clocks are not working, check your soldering points, make sure nothing is being shorted, and make sure your connections are in the correct spot.

If you opted for the RGB LED then read on. Otherwise, go ahead and mount the switch. I used hot glue after mounting the switch in order to make it a little more secure.

Step 4.5 (Optional) Hooking up the RGB LED

The original LED in the NES may not be as clear as the LED you have. You may want to consider sanding yours a bit or the light will shoot out of the NES like a little flashlight.

You are going to have to remove that little board with the LED on it in order to work on it. Once you have access to the LED, go ahead and desolder (or cut) it.

Now wire up the RGB LED before connecting it to the board. You can use whatever colors you want. I used red for normal and blue for overclocked. The color you are going to use for normal mode should be soldered to the side of the switch that has the original oscillator connected to it. Solder the other color to the overclocked side of the switch. Connect the positive side of the board to the center pin on the switch.

NES Power Switch Assembly

NES LED Mod

Not all RGB LEDs are the same so some trial and error may be required to get the right color.

Now solder the LED to the board and make sure it all fits properly.

Test everything again making sure the clocks still work properly and the LED color changes with the clock. If everything looks good, mount the switch.

Step 5 – Clean up

While your NES is still open you may want to consider disabling the lockout chip if you haven’t done so already. Now put it back together and enjoy your suped up NES!

Consider going back and sanding the LED or using a resistor if it is too bright for you…

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From → Mods, NES, Nintendo

One Comment
  1. Great guide. Thank you 🙂

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