My oven died

109A_5

mattmia2 said:

ethicalpaul said:

Correction: $10, and it also has signal injection

That little picture of a square wave on the function dial is a frequency counter.

Except when it is not.

mattmia2

This is a typical accuracy specification for an inexpensive dmm:




1.2% of a 600 ohm scale is +- 7.2 plus 2 so it could read up to 7.5 ohms if the actual resistance is .1 ohm. The meter with that range isn't very accurate for measuring a resistance that low.

ethicalpaul

This is getting pretty deep, but I don't think that accuracy is on the range, it's on the current reading. So reporting about zero ohms as .9 or whatever is pretty out there.

A reading of 7.5 ohms on a .1 resistor would be pretty freaking bad.

mattmia2

ethicalpaul said:

This is getting pretty deep, but I don't think that accuracy is on the range, it's on the current reading. So reporting about zero ohms as .9 or whatever is pretty out there.

A reading of 7.5 ohms on a .1 resistor would be pretty freaking bad.

I don't see how it could be on the current reading rather than full scale, the components and the ad converter don't suddenly change just because the value you are attempting to read is around .1% of full scale. That is why you need an instrument with a lower range if you want to accurately measure that small a resistance (or set up a test rig and measure voltage and current).

ChrisJ

mattmia2 said:

This is a typical accuracy specification for an inexpensive dmm:




1.2% of a 600 ohm scale is +- 7.2 plus 2 so it could read up to 7.5 ohms if the actual resistance is .1 ohm. The meter with that range isn't very accurate for measuring a resistance that low.

According to Fluke this isn't true.

https://www.fluke.com/en-us/learn/blog/digital-multimeters/accuracy-precision


Accuracy refers to the largest allowable error that occurs under specific operating conditions. It is expressed as a percentage and indicates how close the measurement displayed is to the actual (standard) value of the signal measured. Accuracy requires a comparison to an accepted industry standard.

mattmia2

It says it is expressed as a percentage, it doesn't say what it is a percentage of.

The sources of error don't go away just because the value are measuring is a very small part of the full scale reading.(note that the worst case accuracy specifications usually occur at extreme temps and are usually far less at room temp)

ChrisJ

mattmia2 said:

It says it is expressed as a percentage, it doesn't say what it is a percentage of.

The sources of error don't go away just because the value are measuring is a very small part of the full scale reading.(note that the worst case accuracy specifications usually occur at extreme temps and are usually far less at room temp)

So you're saying Fluke is lying?

The specifications for my 179 do not say what it's a percentage of either other than Fluke says it's of the displayed reading and says that's the standard.

Even my Simpson 260 doesn't use full scale for the resistance.
https://www.simpson260.com/260-8/simpson_260-8p.htm

Larry Weingarten

Hi, Cheap, simple, and even I can read it.

Yours, Larry

mattmia2

I'm saying I see a couple vague descriptions like that but I don't see how that is technically possible. The ad converter is still reading some number of bits and if the value it is trying to read is only 1% of full scale if the couple least significant bits have some uncertainty that is going to have a big effect on the reading. A little bit of drift in the resistors that divide the voltage to be read will also have a big effect on the reading.

I would like it to get more accurate as the value being measures gets smaller within the same range, but I won't be convinced until I see an explanation of why it is happening. I have a friend that used to write for test and measurement world, I'll have to ask him about it.

ethicalpaul

If the error value is on the max of the range then why do they make you do the math to calculate it? 

Those tolerances are always on the current value. It would be ludicrous for the same 7 ohm error to exist for a reading of a .1 resistor and a 600 ohm resistor 

mattmia2

ethicalpaul said:

Those tolerances are always on the current value. It would be ludicrous for the same 7 ohm error to exist for a reading of a .1 resistor and a 600 ohm resistor 

Why would it be ludicrous? Ranges exist for exactly this reason. You wouldn't measure a 1.5v cell on the 2kv dc range and expect it to be accurate. You wouldn't try to measure the thickness of shim stock with a yardstick.

mattmia2

BTW, i'm not sure how it is specified but it doesn't make sense that the accuracy of the components would change based on the value being measured, that is why meters have different ranges.

Dave Carpentier

Gettin a bit sidetracked..

So if the element reads the same as when the meter isn't connected, then it's bad.
If it reads like 10 to 50 ohms, it's good.

JakeCK

Anyways, the local ma and pa shop does have it in stock but they closed at 5 and I wasn't going to make there before they closed. Hopefully I'll have it fixed by 10am tomorrow. Almost twice the cost of online but I'm supporting a local company, and I'll have it a week sooner. (39$ vs 22$)

Dave Carpentier

JakeCK said:

I pulled the element and tested it. My multimeter doesn't have continuity so I used the ohms. It gave me a null reading, no change.

Oh, by "null reading, no change" you mean no different than a disconnected meter ?
If so, that would be an open circuit yep.. Im still baffled how that could happen

ChrisJ

Dave Carpentier said:

I pulled the element and tested it. My multimeter doesn't have continuity so I used the ohms. It gave me a null reading, no change.

Oh, by "null reading, no change" you mean no different than a disconnected meter ? If so, that would be an open circuit yep.. Im still baffled how that could happen

The element failed.  They go bad from time to time.

Of course not from power company work with the oven off.

JakeCK

ChrisJ said:

Dave Carpentier said:

I pulled the element and tested it. My multimeter doesn't have continuity so I used the ohms. It gave me a null reading, no change.

Oh, by "null reading, no change" you mean no different than a disconnected meter ? If so, that would be an open circuit yep.. Im still baffled how that could happen

The element failed.  They go bad from time to time.

Of course not from power company work with the oven off.

It was just a very odd coincidence that it failed the next time we tried to use it less than 24 hours after the house got zapped. And like I said it wasn't the only thing to get fried at the same time. 

mattmia2

it could have died near the end of the last time you used it too.

EBEBRATT-Ed

@ChrisJ

How would POCO know the stove was not on? They replace applicances all the time for their screw ups

ethicalpaul

mattmia2 said:

BTW, i'm not sure how it is specified but it doesn't make sense that the accuracy of the components would change based on the value being measured, that is why meters have different ranges.

I guess I can’t convince you with reason so I tell you what. Find me a multimeter that says a 0-1 ohm resistance is 7 ohms and I’ll give you $100

109A_5

ethicalpaul said:

I guess I can’t convince you with reason so I tell you what. Find me a multimeter that says a 0-1 ohm resistance is 7 ohms and I’ll give you $100

@ethicalpaul, don't go there, that is easy with the meter type like @Larry Weingarten posted all you need is the battery to be half dead.

The low Ohms functionality of an Inexpencive meter is usually poor and the cheap probes don't help any either.

The same error is there, with higher resistance values under test you just don't see it anymore, also, often it is out of the range of the display.

ChrisJ

@JakeCK.

I'm sorry I missed that.  What else was fried?

ChrisJ

EBEBRATT-Ed said:

@ChrisJ

How would POCO know the stove was not on? They replace applicances all the time for their screw ups

I couldn't knowingly do that, I'm sorry.

JakeCK

Fix'd, the wife can now bake her meatloaf.

Thanks for the tips, all. 

Also it was a ram module that took a hit too. 

JakeCK

While unrelated to the oven dying, this is the pole that was replaced. They didn't even get it straight. That's going to annoy me for an eternity now. And don't mind the railing post. My deck isn't finished yet. 

mattmia2

I can't respond to that without diving deeply in to michigan politics...

ChrisJ

JakeCK said:

Fix'd, the wife can now bake her meatloaf.

Thanks for the tips, all. 

Also it was a ram module that took a hit too. 

How would a dimm take a hit through the power supply and motherboard and yet neither of those were harmed?

Keeping in mind, most decent power supplies these days can run on 100-240V without anything being changed.

JakeCK

ChrisJ said:

Fix'd, the wife can now bake her meatloaf.

Thanks for the tips, all. 

Also it was a ram module that took a hit too. 

How would a dimm take a hit through the power supply and motherboard and yet neither of those were harmed? Keeping in mind, most decent power supplies these days can run on 100-240V without anything being changed.

Don't know. 🤷‍♂️

Dave Carpentier

Cool that your oven repair ended up quite affordable.
Maybe something happened to the neutral that caused the controller to buzz the element relays ?

I had an oven element stick on during cooking not too long ago. Wife hollered when dinner started smoking and she couldnt turn the temp down. It appeared to be in a runaway condition no matter what we pressed in the controls. Didnt immediately open the door due to the smoke inside. As I stood there baffled, I hear a strong "click". The door just locked itself, as it thought it was in self-clean due to the temperature. Flipped the breaker off and the door eventually unlocked so we could remove the charred remains. Circuit board bad, no longer available. New oven was $$. Started looking at board and (with a magnifying glass) could see the relay carbon pads were stuck together. 5 days later, a set of relays arrived in the mail and my $16 repair was done.
I still wonder, had we been outside or such during this, at what temp would the safety thermal switch have opened and stopped it. Funny design, the controller knew the set temp and it knew the current temp.. and yet it didnt see a problem with it.

109A_5

Hello @JakeCK,

If you truly believe the power outage 'caused' the damage and not just brought your attention to the defects. Your pole transformer probably serves 4 or more houses (its not in the picture). If they had the primary shut down many more houses were probably dark too. Maybe see if any of the neighbors sustained any damage. That would help build a case and maybe you could be reimbursed for your repair costs.

@Dave Carpentier Another DIY win !

mattmia2

Dave Carpentier said:

Cool that your oven repair ended up quite affordable.
Maybe something happened to the neutral that caused the controller to buzz the element relays ?

I had an oven element stick on during cooking not too long ago. Wife hollered when dinner started smoking and she couldnt turn the temp down. It appeared to be in a runaway condition no matter what we pressed in the controls. Didnt immediately open the door due to the smoke inside. As I stood there baffled, I hear a strong "click". The door just locked itself, as it thought it was in self-clean due to the temperature. Flipped the breaker off and the door eventually unlocked so we could remove the charred remains. Circuit board bad, no longer available. New oven was $$. Started looking at board and (with a magnifying glass) could see the relay carbon pads were stuck together. 5 days later, a set of relays arrived in the mail and my $16 repair was done.
I still wonder, had we been outside or such during this, at what temp would the safety thermal switch have opened and stopped it. Funny design, the controller knew the set temp and it knew the current temp.. and yet it didnt see a problem with it.

One of many reasons you shouldn't use an oven unattended.

I mean if the contacts in the relay are welded together there isn't much that the microcontroller can do about it.

JakeCK

109A_5 said:

Hello @JakeCK, If you truly believe the power outage 'caused' the damage and not just brought your attention to the defects. Your pole transformer probably serves 4 or more houses (its not in the picture). If they had the primary shut down many more houses were probably dark too. Maybe see if any of the neighbors sustained any damage. That would help build a case and maybe you could be reimbursed for your repair costs. @Dave Carpentier Another DIY win !

What defects did the outage bring to my attention exactly? We didn't notice the oven until a day later when we tried to make dinner, it had been used with out issue two days before. As of right now I do not believe the outage caused the oven element to fail. It was apparently just a very odd coincidence that it failed either the day before or day after they replaced the pole. The pole being replaced had no baring on that. And the PC, well it's failure to POST brought that to my attention. 

109A_5

JakeCK said:

What defects did the outage bring to my attention exactly?

Are these not defects regardless as to what caused them ? Or maybe you prefer to call them Failures.

1. Failed oven heating element.
2. Failed computer memory.

You initially blamed both on the pole change event.

The oven may have failed "two days before" and gone unnoticed. Or at the point you tried to use it the day after.
The computer RAM who knows when it failed if the computer did not crash. And the re-boot brought it to your attention.

What was the neighbors experiences ???

ChrisJ

109A_5 said:

What defects did the outage bring to my attention exactly?

Are these not defects regardless as to what caused them ? Or maybe you prefer to call them Failures. 1. Failed oven heating element. 2. Failed computer memory. You initially blamed both on the pole change event. The oven may have failed "two days before" and gone unnoticed. Or at the point you tried to use it the day after. The computer RAM who knows when it failed if the computer did not crash. And the re-boot brought it to your attention. What was the neighbors experiences ???

You can run bad ram for a long long time without a problem until it uses that specific bad spot.

It may never crash or it may crash right away.  I think your explanation was perfect.  

JakeCK

I still suspect the ram was caused by the utility. Not the first time nor the last time it'll happen where I've lost hardware during a power failure. And it's unlikely bad ram went unnoticed in that PC... 

As for the oven, reread my original post. I said SUSPECTED. As in not proven either way. Key word. There really isn't much to that oven, some wire, a heating element, an electronic control board and a temperature probe. Had it been the control board it would have very likely been the utility since it is plugged in and on unless the breaker is off. 

Step back and think about this for a second, two electrical failures both discovered with in hours of the utility replacing a pole and causing enough issues that lights flickered and buzzed. and for a short time the house was only on one leg. Siting there telling me I'm wrong to suspect that as a cause is insulting, especially when ya'll can't even agree on how to use a multimeter. Bottom line electronics are sensitive, there's a reason you wear ESD straps when you are working with them, and why you keep fluffy the cat out of the room too. If they're susceptible to a tiny little arc from shuffling your feet across the carpet they are certainly susceptible to an arc out on the pole where there's enough juice to blow you across the yard. 

Now the oven is repaired, thank you to those who offered assistance.

Fyi: the owner of the appliance parts store was surprised the element was bad too from how it looked. He tested it himself just to make sure he didn't sell me a part I didn't need. Apparently, they're pretty obviously bad when they go, normally. Although he did say he sees maybe 2 or 3 a year where there's no evidence. 

ChrisJ

JakeCK said:

I still suspect the ram was caused by the utility. Not the first time nor the last time it'll happen where I've lost hardware during a power failure. And it's unlikely bad ram went unnoticed in that PC... 

As for the oven, reread my original post. I said SUSPECTED. As in not proven either way. Key word. There really isn't much to that oven, some wire, a heating element, an electronic control board and a temperature probe. Had it been the control board it would have very likely been the utility since it is plugged in and on unless the breaker is off. 

Step back and think about this for a second, two electrical failures both discovered with in hours of the utility replacing a pole and causing enough issues that lights flickered and buzzed. and for a short time the house was only on one leg. Siting there telling me I'm wrong to suspect that as a cause is insulting, especially when ya'll can't even agree on how to use a multimeter. Bottom line electronics are sensitive, there's a reason you wear ESD straps when you are working with them, and why you keep fluffy the cat out of the room too. If they're susceptible to a tiny little arc from shuffling your feet across the carpet they are certainly susceptible to an arc out on the pole where there's enough juice to blow you across the yard. 

Now the oven is repaired, thank you to those who offered assistance.

Fyi: the owner of the appliance parts store was surprised the element was bad too from how it looked. He tested it himself just to make sure he didn't sell me a part I didn't need. Apparently, they're pretty obviously bad when they go, normally. Although he did say he sees maybe 2 or 3 a year where there's no evidence. 

I've never worn a static strap when working with assembled boards.   Raw parts yes complete boards no.

I've been building computers for decades and have never had a board damaged by static. 

I expect my power supplies to handle any issues which is why I never use cheap ones.  I usually go with Seasonic or Corsair in the $100-150 range.


I'm sorry if you found this insulting I was only being honest.  I'm not sure how else to say it.

JakeCK

ChrisJ said:

I've never worn a static strap when working with assembled boards.   Raw parts yes complete boards no.

I've been building computers for decades and have never had a board damaged by static 

I've been building them for decades too. And I have suffered  failures from electro static discharge. Do I wear them 100% of the time? No, it depends on how much I care about what I'm working on. If it's one of my own PC's that are years old and won't be bank breaking expensive if something pops I'll skip it. If I'm building a new gaming rig where the video card alone is worth a grand or more you can bet I am. 

JakeCK

Ok why does it keep telling me I need approval for the above comment? it wouldn't let me post yesterday and now I tired to fix a typo and it says it needs approval. O.o

ChrisJ

JakeCK said:

Ok why does it keep telling me I need approval for the above comment? it wouldn't let me post yesterday and now I tired to fix a typo and it says it needs approval. O.o

Don't know, I don't see any messages or anything, just your comment.


I mean no, you can't just sit there building a system on a carpet in the winter. I've never needed a wrist strap, but I don't go out of my way to do something I think will cause a discharge either. The only thing I'd work on with that risk is something using vacuum tubes. They don't care.

I usually sit in the kitchen with the motherboard on the static bag it came in and put it together and then mount it in the case.

Erin Holohan Haskell

JakeCK said:

Ok why does it keep telling me I need approval for the above comment? it wouldn't let me post yesterday and now I tired to fix a typo and it says it needs approval. O.o

Sorry @JakeCK, your comment got swept up in a spam filter for the term "gaming." We filter out a lot of spam related to online casinos and gaming. Thanks for your patience. I've sent it through.