Most cockroaches like to gather and lay their eggs in places that are secluded, warm and close to sources of food and water. Unfortunately, the interiors of many electronic appliances, including TVs, radios, clocks, cable boxes, video game consoles and computers, fit that description, and cockroach infestations of these kinds of appliances and devices are common.
Infested electronics are also a common avenue by which roaches to travel from one home to another. Cockroaches may be introduced into a home in used electronics that have come from an infested area, and you may transport roaches to your new home when you move by carrying infested electronics with you.
In some cases, it's possible to kill cockroaches inside electronic appliances using a non-chemical method that won't harm the appliance. In other cases, the best course of action is to use insecticides to kill the roaches when they venture outside the appliance.
Cockroaches can't survive in extremely cold temperatures, and exposing them to temperatures close to 0 degrees Fahrenheit for a prolonged period of time often effectively controls an infestation.
If roaches have infested a small appliance, seal the appliance inside a plastic bag and put it in the freezer for five days; subjecting the roaches to cold temperatures for a shorter period of time may not kill all adult roaches, nymphs and eggs. If you live in a cold climate and outdoor temperatures will remain consistently below 0 degrees for five days or longer, you can put the bagged appliance outside in an unheated garage or outbuilding to achieve the same effect.
In the case of large appliances or devices that can't safely be exposed to cold, baits or dusts can be used to kill roaches as they move into or out of the electronics. Baits and dusts can also be used to kill roaches that have infiltrated electrical outlets, which roaches often use as pathways into wall voids.
Dusts containing boric acid, silica dioxide or diatomaceous earth kill roaches after the insects walk through them. Spread the dust in a very thin layer in places where roaches travel, such as under and behind appliances.
Bait stations typically contain insecticidal gels, and when roaches discover the bait, they mark the location, an action that can lure roaches out of their hiding places. The slow-acting insecticide kills roaches that eat it, and it also kills roaches that eat the feces and dead bodies of other poisoned roaches. Place baits in corners where roaches are active near electronics.
Insecticidal sprays containing permethrin, deltamethrin, cyfluthrin, or cypermethrin kill roaches quickly, but they usually don't have the residual effect that baits and dusts have.
After you've killed the roaches inside your electronics, thoroughly clean the devices to remove dead roaches, eggs and feces. Always unplug appliances before you attempt to clean them, and don't use water or liquid cleaners on electronics or electrical appliances. Brushes, compressed air and soft cloths work well to clean electronics.
Be aware that opening the case of some electronic devices may void the device's warranty, and cleaning up after a severe infestation can be a difficult and delicate job, so it may be best to seek the help of professional in the case of an infestation of expensive electronic equipment.