How to use Deoxit D5

Retro computer enthusiasts and computer technicians either love or hate Deoxit D5. There’s no middle ground with it. But I think the hate comes from people misusing it. Used sparingly, Deoxit D5 seems like a miracle cure. Here’s how to use Deoxit D5, and when.

The key to Deoxit D5

Of course, Caig Laboratories, the makers of Deoxit, aren’t going to tell you exactly what’s in it. They bill it as a combination of a cleaner, oxidation remover, and conductivity enhancer. It sounds like black magic. But its claims aren’t that far off what WD-40 claims to be. WD-40 actually claims to be all of that and more.

There’s little doubt Deoxit D5 is a combination of oil and solvents, much like automatic transmission fluid. Automatic transmission fluid has similar properties, to help keep your car’s transmission from rusting out. It probably also contains a chemical additive to improve conductivity like No-Ox-ID has. No-Ox-ID helps protect electrical connections in harsh environments, and model railroaders have been using it for decades to make their notoriously finicky track conduct electricity better.

The key with any conductivity enhancer is to use it sparingly. A little goes a long way. Small quantities of it help metal to retain or regain its conductive properties. But like any oil, too much of it makes it an insulator, completely defeating the purpose. When you flood a connection with it, your only recourse is to let it evaporate, or clean it off as best you can with a solvent like mineral spirits.

It’s hard to find Deoxit D5 in retail stores so I usually buy it online.

How to use Deoxit D5

You can use Deoxit D5 just the same way you would use any other contact cleaner, except you need to use it sparingly. Most ordinary contact cleaner is just mineral spirits and propellant, so it dissolves and disperses impurities and then evaporates quickly. Deoxit evaporates much more slowly, so the consequences of flooding a connector with it are much greater. Flooding a connector with mineral spirits doesn’t harm anything, other than wasting money.

To use Deoxit, just spray a small amount into the connector that’s giving you trouble. A quick burst while moving the can left to right will do the trick. If you think you’re using enough, you’re probably using too much. If you want, you can then plug something into the connector to help move it around, but you don’t need to scrub. Deoxit works chemically, not mechanically. Coating the entire surface helps it to work, but scrubbing with it doesn’t help anything. And if you’re patient, capillary action will draw it into the surface anyway. Deoxit will frequently show an immediate improvement, but sometimes its full effect doesn’t really take effect until 24 hours have passed.

On older systems with chips in sockets, you can use Deoxit for two things. You can use it to restore conductivity between the socket and the chip’s pins. You can also use it to help free a chip that doesn’t want to come out of its socket. Its lubricating properties are a nice side effect in that case.

If the problem is a chip not working, it’s best to remove the chip, spray Deoxit D5 into the socket, then replace the chip. This gets Deoxit D5 into the areas where it needs to work more quickly. If you spray it onto the chip without removing it from the socket, it takes longer for capillary action to draw it in. It will still work, but you’re more likely to need to wait 24 hours to see the full effect.

What Deoxit D5 can help

I’ve used Deoxit D5 on slot connectors, ports, chip sockets, dials, switches, and cartridge connectors on game systems. Anything that involves  mechanical connection and a flow of electricity afterward. It can restore balky power switches, and I’ve especially found it helpful on cartridge connectors in old game systems. The Nintendo NES is the system that most frequently needs help, but I’ve also used it on Atari 2600s.

Cleaning up from the misuse of Deoxit

If someone flooded a system with Deoxit and now it’s worse, cleanup is fairly straightforward. Spray the affected area with regular contact cleaner. The blast will help it penetrate into hard to reach areas. The mineral spirits in the regular contact cleaner dissolves oil very readily.