Risks associated with fitting electronic parts

So we’ve arrived, had quick look at your washing machine and have narrowed it down to a likely “Control Board” fault. “Likely” being the operative word! Because no one in our industry is able to diagnose a faulty control board accurately. To do this takes schematics and component specifications and expensive test equipment that is better suited to a lab than a van.

Further, the suppliers of the electronic parts will not refund any electronic parts once removed from its packaging. And for good reason, PCB’s are electrically sensitive, and can be damaged if any other electrical parts are within the unit is faulty. Or from static electricity charges. Suppliers have no way of knowing what happens to the PCB once removed from its package, so they can’t or wont take these parts back.

Deductive reasoning

Not to get to technical; but for most device faults, we use deductive reasoning. Which basically means we can test certain conditions of a device which will give us a high probability that the device is faulty or not. For instance a motor with an open circuit will not work unless the circuit is closed. It’s straight forward, we measure the resistance and we look for a specific result.

Simple example (Wikipedia)

An example of a deductive argument:

  1. All men are mortal.
  2. Socrates is a man.
  3. Therefore, Socrates is mortal.

The first premise states that all objects classified as “men” have the attribute “mortal”. The second premise states that “Socrates” is classified as a “man” – a member of the set “men”. The conclusion then states that “Socrates” must be “mortal” because he inherits this attribute from his classification as a “man”.

Inductive Reasoning

Inductive Reasoning is basically the opposite of Deductive Reasoning. We use the logic that if all components in the machine are testing correct then the PCB must be faulty. So it allows for the possibility that the PCB is not faulty. But is the most logical conclusion.

But to determine if a printed circuit board (PCB) means spending time verifying the other electrical devices like the motor, inlet valves, pumps, door locks, etc are correct. To do this we rely on resistance readings. This means isolating each device and checking for the correct resistance readings. Sadly resistance is only one element of ohms law. Which means it doesn’t provide proof positive the device is functioning correctly.

Simple explanation (Wikipedia)

Unlike deductive arguments, inductive reasoning allows for the possibility that the conclusion is false, even if all of the premises are true.[4] Instead of being valid or invalid, inductive arguments are either strong or weak, which describes how probable it is that the conclusion is true.

Economics

Unfortunately the cost of the diagnosis time can be as expensive as the repair itself and generally ends in the repair becoming uneconomical.

Example: (not real values)

Call out $100
Diagnosis Labour 1 1/2 hour $165
Electronic Board $220
Installation Labour 1/2 hour $55
Total    $540

Given the cost of a new machine of $650.oo it is difficult to justify proceeding with the repair.

There are many factors that would drive this final decision, such as age, condition, brand (original value), new price etc. For instance if the machine was just 2 years old and a power outage had caused the PCB to be damaged then it might be sensible to repair the machine. But if the machine was 7 years old and was not in good nick then repairing the machine would not make much sense.

So, the reason this page exists is to save our technician from having to spend 15 minutes trying to explain these details so that you can make an informed decision. And to advise you (the customer) that if you do decide to go ahead and replace any electronic part such as the PCB, we won’t be held liable for the outcome. And once we remove the electronic part from its packaging, you the customer are liable to pay for it regardless of the outcome. Further the electronic part cannot be returned.