How to repair contact failure

Cables are indispensable for connecting devices like guitars and amps. They play an important role in transmitting sound signals between equipment. Metal parts called connectors are attached to both ends of the cable, and by inserting the connector into the input / output connectors of the equipment, the signal transmission from the terminal inside the connector to the terminal of the receiving equipment is carried out. The figure on the right is a cannon connector used for a general microphone cables, etc. The metal visible inside the connector are the terminals. Transmission of signals between the terminals is performed in a very simple manner, merely by bringing the terminals into physical contact and transmitting electrical signals.

Not only the connector but also the parts used to control the volume used in analog equipment such as electric guitars are similarly structured to control the volume using signal transmission by physical contacts inside the controller. The only reason why contact transmission is used is that this method is the least expensive and most reliable. When plugged in, the signal will flow, and when unplugged it will stop. It is only natural.

However, the metal surface of the terminal may be oxidized, and furthermore, dust and dirt may accumulate, which may cause a situation where the conduction becomes worse. It results in a so-called short or generates crackling noise. These symptoms are collectively called contact failure and contact failure causes poor signal transmission. What should you do if such a contact failure occurs?

Of course, when the condition is bad, it is necessary to replace parts such as connectors and pots. To some extent, mild problems can be fixed by yourself. First of all, what you want to check is to move the contacts around. These include inserting and removing connectors several times and turning the volume knob several times. In this way contact may be revived, and the confirmation of the situation and the reason for the lack of sound will also help determine where the problem really lies. That said, it will be only a temporary solution even if it is fixed by the above method.

The use of contact rejuvenating agents is recommended as an effective method to permanently improve contact defects.

CAIG D5S6

CAIG G5S6

If contact failure is occurring in the connector, first apply contact cleaner on the male connector terminals. There are various types of contact cleaners, but the spray type is very convenient. After spraying a small amount, with the contact cleaner applied to the terminals, remove and insert the connector. Next, if contact failure occurs in a pot or fader, first make rotate it to zero or full, and spray the contact rejuvenating agent into the internal resistor. After spraying, move the shaft and knob around evenly.

Repeat these tasks several times depending on the severity of the contact failure. Contact cleaner cleans the contacts, forms a protective film on the contacts, and restores the contacts.

※ In pots and faders, this method can be used only if the structure inside the parts can be accessed. There is no alternative to replacing pots that are sealed with molds.

In addition, there are other methods in the case of open type parts (typically made by SWITCHCRAFT) in which the phone connector used for the electric guitar or the base or the terminal is exposed. This type of terminal is formed by bending metal and has a spring-like structure. If you use it, the effect of the spring becomes loose, and the terminal itself may be deformed. In other words, the contact point will be lost due to the position or deformation of the terminal. In this case, if thin pliers are used and the terminals themselves are bent, the contacts may be restored.

In some cases, the symptoms may get worse, as it will be quite delicate work in terms of the degree of force, the angle of the terminal, and the method of bending the terminals. If you cannot fix it with contact point rejuvenating agent, you should try this method before giving up. By the way, this method is also practiced in the field of repair.

Contact failures may occur even with new plugs and jacks. For example, there is no problem usually, but there is a problem with sound cutting out only when using a specific device. This is a compatibility problem between the plug and jack, which is a rare problem. Both are non-defective products, so there is no way to fix them alone, and the symptoms do not reappear except in certain situations, so they are annoying. In order to reduce these risks, the idea exists to match the plug and jack manufacturer. If you keep this in mind, it will help when deciding the best solution to the problem.