Taking microwave oven apart

THE_RB

Joined Feb 11, 2008
5,438
Yeah, what's unforgivable; is to watch someone use an adjustable wrench.....backwards.;)
Oh they definitely have a forwards and a backwards. The adjustable jaw is weak, so you turn the nut in the correct direction the point of the nut places leverage against the inside area of the jaw. If you turn them backwards the nut places leverage on the weaker outside area of the jaw and can bend or break it etc. Every beginner knows that! :)

But the left handed one really ticked me off. The proper ones (I have about 10) close the jaw when the right hand thumb pushes forward (away from the hand). It's very natural. It's the first time I had ever seen a left handed one. But I've never been to Canadia.
 

inwo

Joined Nov 7, 2013
2,419
That's what I meant be left hand. The worm screw threads.

Sorry, didn't notice that is what you were referring.

Canadian model? Spell check likes it?:D
 

richard.cs

Joined Mar 3, 2012
162
Something interesting has just happened.

The transformer has been disconnected from the capacitor for a couple of days now, so I thought it was pretty safe to handle.

I had to put it on the floor for a second to make room for something, and the second it touched the floor I saw little sparks around the external connectors. They stayed for about a second.

I'm trying to think of a reason for this. I don't think this electrostatic discharge, since the connectors are conductive.

Any ideas?
HV capacitors can recover charge if they're left open-circuit, that's why they should always be stored with a bleeder resistor or shorting clip. Still, I've only ever found 1 microwave where the bleeder resistor wasn't internal to the capacitor. If it's external it must be disconnected or broken, if it's internal it must be broken. Either way it's good practice to fit a shorting link across the terminals after the capacitor has been discharged.

The charge stored in the dielectric may be modelled as a small capacitance with a very high series resistance in parallel with the bulk capacitance. Over time this bleeds into the bulk capacitance charging it up, potentially to dangerous levels.
 

tcmtech

Joined Nov 4, 2013
2,867
A kid at work installed one backwards, and upside down.
At one of my first jobs as a service tech I had a boss who thought he was gods gift to the service industry because in his mind he knew everything about everything.

Anyway one week he ordered a case (10 or 12) of new band saw blades for our shop saw.

A week or two later I and one other guy needed to change blades on the saw but could not find the new sets. We asked our all knowing boss where he put them and he promptly said he sent them all back because "the idiots who made them for us" made them inside out.
Apparently when they came in he had tried to put a new one on and he found it was backwards when he unfolded it. So was the next one and the next one and the rest after that. :rolleyes:

That was one of my first lessons on how those who manage others are not necessarily smarter or more knowledgeable than those whose work they oversee. :mad:
 

inwo

Joined Nov 7, 2013
2,419
There are two kinds of people.
Those that can fold a band saw blade and those who cannot.:D

I am sorry to say, I cannot.:(

I have done it, but a week later I forget.:cool:
 

ian field

Joined Oct 27, 2012
6,536
At one of my first jobs as a service tech I had a boss who thought he was gods gift to the service industry because in his mind he knew everything about everything.

Anyway one week he ordered a case (10 or 12) of new band saw blades for our shop saw.

A week or two later I and one other guy needed to change blades on the saw but could not find the new sets. We asked our all knowing boss where he put them and he promptly said he sent them all back because "the idiots who made them for us" made them inside out.
Apparently when they came in he had tried to put a new one on and he found it was backwards when he unfolded it. So was the next one and the next one and the rest after that. :rolleyes:

That was one of my first lessons on how those who manage others are not necessarily smarter or more knowledgeable than those whose work they oversee. :mad:
Its not what you know - its who you know.
 

Thread Starter

ElectricMagician

Joined Jul 26, 2012
57
#12 said:
Did you leave the bleed off resistor connected as I told you to do? If so, better check it for being bad. Open. Infinity ohms.
HV capacitors can recover charge if they're left open-circuit, that's why they should always be stored with a bleeder resistor or shorting clip. Still, I've only ever found 1 microwave where the bleeder resistor wasn't internal to the capacitor. If it's external it must be disconnected or broken, if it's internal it must be broken. Either way it's good practice to fit a shorting link across the terminals after the capacitor has been discharged.

The charge stored in the dielectric may be modelled as a small capacitance with a very high series resistance in parallel with the bulk capacitance. Over time this bleeds into the bulk capacitance charging it up, potentially to dangerous levels.
The capacitor was disconnected altogether from the transformer
 

Metalmann

Joined Dec 8, 2012
703
At one of my first jobs as a service tech I had a boss who thought he was gods gift to the service industry because in his mind he knew everything about everything.

Anyway one week he ordered a case (10 or 12) of new band saw blades for our shop saw.

A week or two later I and one other guy needed to change blades on the saw but could not find the new sets. We asked our all knowing boss where he put them and he promptly said he sent them all back because "the idiots who made them for us" made them inside out.
Apparently when they came in he had tried to put a new one on and he found it was backwards when he unfolded it. So was the next one and the next one and the rest after that. :rolleyes:

That was one of my first lessons on how those who manage others are not necessarily smarter or more knowledgeable than those whose work they oversee. :mad:



That was funny. Yeah, I've seen some pretty retarded crap like that happen in the shops.;)
 

shortbus

Joined Sep 30, 2009
10,045
There are two kinds of people.
Those that can fold a band saw blade and those who cannot.:D

I am sorry to say, I cannot.:(

I have done it, but a week later I forget.:cool:

Take the saw loop and holding it step on the part near the ground. Grab the top with your hand, palm down, knuckles pointing toward your body(you have to twist the wrist). Holding on to the blade, untwist the wrist while moving hand toward the floor. The blade will go into three smaller loops or rings every time.

During my apprenticeship I welded hundreds of blades and this was the easiest way of looping them. Works every time.:)
 

shortbus

Joined Sep 30, 2009
10,045
That was funny. Yeah, I've seen some pretty retarded crap like that happen in the shops.;)
I still think of the foreman that used the drill press that had a reverse in it, for power tapping, to try and drill some holes with it. After a few minutes he was cussing, whoever sharpened the drill bit last. One of the guys went over and put the drill press in forward and drilled the first hole for him. Then shut the drill off and put it back in reverse and walked away. Boss tried again to drill another hole, then gave the job to the apprentice to finish and went back into the office. No one ever told the boss the "secret".
 

inwo

Joined Nov 7, 2013
2,419
Take the saw loop and holding it step on the part near the ground. Grab the top with your hand, palm down, knuckles pointing toward your body(you have to twist the wrist). Holding on to the blade, untwist the wrist while moving hand toward the floor. The blade will go into three smaller loops or rings every time.

During my apprenticeship I welded hundreds of blades and this was the easiest way of looping them. Works every time.:)
Easy for you to say...........:D
 

THE_RB

Joined Feb 11, 2008
5,438
...
Apparently when they came in he had tried to put a new one on and he found it was backwards when he unfolded it. So was the next one and the next one and the rest after that. :rolleyes:
...
I make a case for stronger Darwinism being needed. At least neuter the guy so those genes can't continue. ;)
 
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