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Repair guide

Clean or replace the NES 72-pin cartridge connector

The front-loading NES connector wears, bends and corrodes, and it is the best-known reason these consoles stop booting. Cleaning fixes many units, and a new connector fixes the rest.

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Cartridge · Medium · about 60 minutes. Worth doing. Reports say this fix helps on many machines.

You are in the right place if: The power light blinks, the screen flashes grey or blue and games only boot after a lot of wiggling.

Before you start

  • Do not use Brasso, sandpaper or magic eraser on metal pins. ConsoleMods warns this can strip the plating.
  • Do not blow into cartridges. Saliva causes corrosion.
  • If pads lift or traces tear during desoldering, stop and ask an experienced repairer rather than improvising.

Board revisions and models

Front-loading NES only. The NES-101 top-loader and the Famicom use different cartridge connectors, and PAL units use different lockout chip variants, but the connector job is the same idea.

Parts you may need

  • 72-pin NES cartridge connector. new connector with tight springy pins Amazon · eBay
  • Isopropyl alcohol 90% or higher. cleaning contacts Amazon · eBay
  • Contact cleaner. optional for stubborn grime Amazon · eBay

Tools

  • Cotton swabs and lint-free cloth. cleaning Amazon · eBay
  • Dental pick or needle. remove debris from the slot Amazon · eBay
  • Soldering iron, flux, wick or desoldering pump. connector swap Amazon · eBay
  • Multimeter. check for bridges Amazon · eBay

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Step by step

  1. Rule out the game Try a cartridge you know works. Clean its edge contacts with an alcohol swab and let them dry fully before testing again.
  2. Open the console Unplug it, flip it over and remove the bottom screws. Photograph the layout, then lift out the shield and board so the connector is reachable.
  3. Inspect the connector Look for bent or flattened pins, hair, dust and green or white corrosion. Pick out debris with a needle or dental pick.
  4. Clean the slot Wrap a cloth dampened with isopropyl alcohol around an old credit card and slide it in and out of the slot several times until it comes out clean.
  5. Dry and compressed-air it Blow out the slot with compressed air and let everything dry before power is applied.
  6. Test loosely assembled Reconnect video and power with the board still accessible and try several games. If it boots reliably, reassemble and stop here.
  7. Desolder the old connector If it still blinks, remove the connector. Use flux, wick or a pump and work pin by pin so you do not lift pads.
  8. Fit the new connector Clean the pads, seat the new connector flat and square, tack two end pins, check alignment, then solder the rest.
  9. Look for solder bridges Inspect every pin under magnification and check neighbouring pins for shorts with a multimeter before reassembly.
  10. Reassemble and soak test Close it up and run a few different games for 15 minutes or more, reseating cartridges a few times to confirm it holds.

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us.

  • Story (Medium confidence). A PAL NES with a blinking light and flashing screen was cured by a modern replacement 72-pin connector plus cleaned cartridges. Source
  • Tip (Medium confidence). ConsoleMods recommends an eraser on cartridge pins after the alcohol swab, then wiping up the debris and retesting. Source
  • Watch out (Medium confidence). The original NES is described as unreliable largely because of this connector design, so a worn one is expected on most surviving units. Source

Guides we used

We wrote the steps in our own words from these. They have the photos and the full detail, so please read them and support their authors.

Boards and models vary, so check what is in front of you. A repair can involve hot tools, chemicals and, on some machines, dangerous voltages. You do it at your own risk.

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