Appliance repair used to be the exclusive domain of electricians, but as whitegoods became cheaper this type of work went out of style. But, David Herres says, there’s still money to be made as a service technician.

When an electrical appliance malfunctions it is quite often an electrician that is asked to investigate. Some electricians avoid this type of work, believing it to be outside of their job description. But most of us have seen slow periods due to worldwide economic fluctuations and we have found it beneficial to open new revenue streams.

Appliance repair is certainly fertile territory. Your existing knowledge and expertise as well as the tools you already possess mean you are well-positioned to enter this field without much difficulty.

That said, we have to face the fact that some types of appliances and repairs are refractory if not stubborn, not admitting of an easy fix. Still, there are ways of coping, and the more you do it the easier it will be to prevail.

To begin, we need to distinguish between commercial and consumer appliances, as found in a home. Surprisingly, commercial machines are often much easier to work on. They are larger and less compact. You can use your cordless drill with a socket and extension to unbolt an access plate and look around inside. In contrast, consumer appliances often come apart in odd ways and when it comes time to refasten the outer panels, you may have to struggle to align everything correctly so that it will bolt back together.

YouTube videos are immensely helpful with this. Simply type the make and model of any appliance into the search bar and you will find numerous how-to videos showing disassembly and trouble-shooting techniques. Other internet resources are valuable as well. We’ve all seen cryptic and puzzling error codes on the alphanumeric display of a microwave oven or similar appliance. It may say “Error Code E 14” or something similar. Google the error code plus make and model and you will see a translation along with the suggested repair procedure. The search results will also include links to online tutorials and forums where professionals give advice and insight.

Additionally, from the manufacturer’s website, you can usually download free schematics and operator’s and service manuals that will provide all the information you need to succeed in repairing the appliance. There are also print resources.

Ordinary troubleshooting techniques are applicable to most appliance repair scenarios. When the unit is completely dead, that is it won’t power up at all, that is often an easy repair. If it is cord-and-plug connected, first make sure that there is power at the receptacle. Then, there is usually a small access plate close to where the power cord enters the enclosure. Remove it and measure the voltage at the input terminals. If it is a 240V appliance, make sure that both legs are live with respect to each other. Use your neon test light to check that the equipment ground is intact.

Wiggle the cord from side to side, along its length and especially at the strain relief where it enters the enclosure, to see if this brings out an intermittent fault. If your investigation so far has not revealed the fault, you will have to go deeper.

If it is a motorised appliance, measure the voltage at the motor input. If these terminals are live, you have to face the fact that the motor may be dead. To check it out, power down the entire appliance by unplugging it or, if hard-wired, opening and locking out the disconnect or branch circuit breaker at the entrance panel or load centre. Then use your ohmmeter to measure the resistance to ground of the line terminals. You have to measure high megohms, or it means the winding is grounded out. If that is the case, it means the winding insulation has broken down and the motor needs to be replaced or (if it is a large, expensive motor) sent out to be rebuilt. Or, conceivably, there could be a superficial wiring fault inside the enclosure.

If there is no voltage at the motor input, there are several possibilities. In any motorised appliance there are control devices in series with the motor. Starting at the upstream end, with the unit powered down, these control devices can be checked with an ohmmeter. The first and most obvious, and a frequent offender, is the ON-OFF switch. Quite often it becomes open and takes down the entire appliance. Measure for continuity and see if the switch does what it should when toggled. Also, wiggle the switch from side to side to find out if it is noisy. A generic replacement is sometimes available, but be sure it has the correct amp rating. It may be necessary to obtain a proprietary switch at greater cost. If there is a problem getting the switch you need, you may have to drill a hole in the sheet metal and install a common toggle switch. Here again it is essential to match or exceed the amp rating of the original switch.

Next on the agenda is to look for a fuse. It may have a tubular glass package or be a newer plug-in type, similar to an automotive fuse. It is usually (but not always) possible to determine visually if it is blown, but to be sure, check with the ohmmeter. Or, if the appliance is powered up, measure the voltage drop across the fuse. Put your probes on either side. If there is voltage, the fuse is open. Actually, switches, timers and other control devices may be checked in the same way, and that is perhaps the more professional way to proceed.

If the fuse has blown many technicians figure their problems are over and just throw a new fuse at it. The problem with that approach, however, is that the fuse may have performed its protective function in response to a downstream heavy current fault. Complicating the situation is the fact that this fault could be intermittent, the result being that you would declare the appliance fixed only to be called back soon after. The best course of action is to check downstream, visually and with the multimeter, to ascertain if there is an underlying problem.

On the other hand, sometimes fuses open and there is no other fault. The element can become fatigued with repeated thermal cycling, or it could have opened because of a transient voltage spike in the power supply, caused perhaps by a lightning strike in the vicinity of a utility power line.

There are other control devices in series with the motor or other load, and any one of them can keep the appliance from running. Many appliances such as a microwave oven, washing machine or dryer have a door that the user opens to get at the contents. These doors generally have an interlock switch that cuts power to the appliance when the door is open. The switch or associated mechanical linkage may go bad. If the switch is open or the linkage gets loose the appliance will not run, and this is a simple repair. Under no circumstance should this or any other protective device be shunted to get the appliance working, or the user could be injured.

Other in-series control devices include temperature sensors to detect overheating; timers (which are ordinary ON-OFF switches); and, motor overload devices, either inside or outside of the motor. Any of these can become defective and prevent normal operation. All of them can be checked with either an ohmmeter or a voltmeter.

Some appliances, such as a kitchen range or wall-mounted oven, have the power flow terminate in a heating element and often that is the culprit. If the unit powers up (oven light, clock, power lights) but no heat is forthcoming, you would usually be correct to assume that the element has gone bad. Most of the time, with the aid of a good work light and common mechanic’s tools, you can remove the element. If it is open, that is not always visually apparent. An ohmmeter check will be definitive. There is no repair for a bad element. It will need to be replaced.

Domestic hot water heaters often suffer the same burnt-element syndrome. They usually have two elements, upper and lower. The elements are intended to operate only while totally immersed in water. If the water level goes down below the element, it will instantly burn out. For this reason, the top element is more likely to burn out. Most homeowners believe that to replace the element is a costly job, but this is not true. Generic elements are inexpensive and replacement is quick and easy.

• STEP ONE: Power down the heater.
• STEP TWO: Turn off the water supply and drain the water. If you open the pressure relief valve, the water will drain faster.
• STEP THREE: Remove the access panel, disconnect the two wires and check the element with your ohmmeter.
• STEP FOUR: Unscrew the bad element(s) and replace. If a gasket is damaged it will have to be replaced. Re-attach the wires.

Refill the tank with the hot water faucet open. Check for leaks. Do not power up the hot water heater until you are sure it is full, with a clear stream coming out of the hot water faucet.

We have outlined some of the simpler appliance repairs. It gets a lot more complicated. The way to get into this interesting work is in an incremental fashion, progressing to more difficult repairs as you gain experience, the whole time consulting print and internet resources for guidance.