Repaired my microwave today

[Lo_volt]

A few months ago, my microwave started tripping the circuit breaker whenever anyone pulled the door open while the magnetron was running. It never happened when we paused or stopped cooking before opening the door. Yesterday, my daughter pulled the door open in that specific manner and the microwave stopped working altogether. I checked the breaker and it wasn't tripped. It seemed the microwave was bricked.

Today I had the opportunity to open it and I found that the internal fuse was blown. The unit had a service pamphlet tucked inside so i pulled it out and looked it over. There was a whole section about a "monitor switch". I had to google what that was and interestingly enough, its function is to blow the fuse if it is still closed while the magnetron is energized i.e. door open and magnetron on. Being a 20 amp fuse it was a toss up whether the internal fuse blew or the house circuit breaker tripped. Finally, yesterday, the internal fuse bit the dust.

In poking around inside, I found that the monitor switch was very loose in its mount. A layer of tape tightened it up. Apparently the loose switch was still closed while the door interlock switches said the door was open and magnetron running. The tape tightened the switch in its mount and fixed the issue.

I guess this post is a heads up that GE microwaves have a monitor switch.

It's also a bit of a complaint that there's no indication of that specific fault. Those who are less technically inclined would likely have tossed the unit and bought a new one. This despite the possibility of a cheap fix.

 

[starLED]

I know loads of people who have had mains shocks (I've had loads myself ), but I don't know anyone who has had a shock from a Microwave. I've only heard one story about such a case, and the guy was lucky - Paramedics happened to already be next door, they were there in seconds, and able to resuscitate him - but according to the story, he was never quite right afterwards.

I once wanted to repair my microwave oven for faulty LCD screen. I even posted here for an advice.
As I was searching on the web for oven repair, I read that "The U.S. Consumer Product Safety Commission reports that four people are electrocuted each year trying to repair their microwave ovens.".
It wasn't clear to me at first why, but then I read there are high voltage capacitors, I think 2000V in ovens that people do not discharge and it was the reason they got killed.
I was very nervous to continue, but then I realized that those capacitors needs to be discharged with high ohms resistor, and not as some do with pair of pliers shortening the capacitor terminals.
I eventually gave up because I was not confident in my very smart brain and experience.

There was even a case where repair person was electrocuted in a repair shop while diagnosing the problem with a microwave oven.
Appliance repair person was electrocuted in a repair shop while diagnosing the problem with a microwave oven--Maryland

 

[Nigel Goodwin]

I once wanted to repair my microwave oven for faulty LCD screen. I even posted here for an advice.
As I was searching on the web for oven repair, I read that "The U.S. Consumer Product Safety Commission reports that four people are electrocuted each year trying to repair their microwave ovens.".
It wasn't clear to me at first why, but then I read there are high voltage capacitors, I think 2000V in ovens that people do not discharge and it was the reason they got killed.
I was very nervous to continue, but then I realized that those capacitors needs to be discharged with high ohms resistor, and not as some do with pair of pliers shortening the capacitor terminals.
I eventually gave up because I was not confident in my very smart brain and experience.

There was even a case where repair person was electrocuted in a repair shop while diagnosing the problem with a microwave oven.
Appliance repair person was electrocuted in a repair shop while diagnosing the problem with a microwave oven--Maryland

Exactly, the unfortunate repair person was incompetent, and didn't know what he was doing - hence the strict regulation in the UK.

You don't mess with Microwave Ovens.

Colour TV's have 25,000V, but it's low current, so not particularly dangerous - although you could fall over from the shock, and break your neck.

 

[starLED]

Exactly, the unfortunate repair person was incompetent, and didn't know what he was doing - hence the strict regulation in the UK.

No, I read that he was very competent and experienced 43-year old repairman with his own business.
He was apparently overtired and somehow got shocked while oven was plugged in.

The victim placed the oven on a workbench and removed the cover. He had
positioned himself between the two individuals who were working in the shop
that day. The victim plugged the oven into a power strip that ran the length
of the workbench. The power strip was designed to have continuous contact
points throughout its entire length for electrical plugs, but provided no
inlet for a grounding prong.
According to a witness the victim began to examine the oven while it was
plugged in to the power strip. Reportedly, the fan motor of the microwave
oven was heard, and presumably the oven was operating, when the victim placed
his hands somewhere inside the circuitry of the oven. The witnesses heard the
"pop" of an electrical arc and saw the victim rocking to and fro. One witness
pulled the electric plug as the victim fell to the ground.

 

[Nigel Goodwin]

No, I read that he was very competent and experienced 43-year old repairman with his own business.
He was apparently overtired and somehow got shocked while oven was plugged in.

That's not a description of 'competent'

There's no 'somehow' about it, you don't get shocked while working on a microwave oven.

 

[starLED]

From the report:

The victim was an independent business owner who had been in the consumer
electronics and appliance repair service business for at least five years.
The victim was the sole employee of the business. Because the victim handled
a high volume of work he would occasionally bring overflow work to one of the
witnesses, who also ran an appliance repair service. No evidence of a safety
program or regular safety training was found. The victim was believed to be
an experienced electronics and appliance repair-person.


The exact cause of shock is not clear, but in report says:

It is unclear what part of the oven circuitry the victim contacted, but there
are exposed components that would have been energized while the oven was in
operation. An electrical connector plug that attached to the magnetron was
found to be unattached following the incident and the corresponding prongs on
the magnetron appeared to be slightly bent together instead of parallel as the
design requires. According to the witness who inspected the oven following
the event no other readily visible problems were identified. The oven was not
available for further tests or inspection.