what a wonderful idea... risk the food go bad and sending people to hospital. and not because of some failure but because mains frequency changed 0.5Hz. as if performance of fridges or air conditioners in Europe is not already nearly useless crap. every time i visit, frown at what they serve as "cold drink". and don't get me started on what they call an "air conditioned" room.

It wasn't quite like that. It started off as an idea to detect when the grid was heavily loaded by the fact that it slows down, just like any other generator. Then the idea was those who switched off appliances when the frequency was lower could have cheaper electricity. There was nothing mandatory about switching things off, if refrigeration appliances needed to cool they could still use electricity but it would be more expensive.
Before it got going it was replaced by connecting things to the internet, so that they could be impossible to get working, would be in laundry rooms out of the range of the router and allow hackers to gain access to your data because of poor security, and make it difficult to design compliant appliances, whereas detecting a change in frequency is something any engineer could do.
But @nsaspook is correct. Deliberately changing the frequency of a whole country full of connected synchronous generators wouldn't be easy.
By the way, not everyone wants their drinks ice cold, I much prefer my beer at cellar temperature (10°C)

. . . but we digress.

 

and don't get me started on what they call an "air conditioned" room.

You know, not everyone wants a 68F room temp, I keep my house 76 in the summer because that is the temp I am comfortable at in shorts. When I go out shopping or dining, I have to wear a jacket indoors. And then the same idiots who keep it at 68 in the summer bump it up to 75 in the winter when everyone is dressed for cold. Go figure.

 

You know, not everyone wants a 68F room temp, I keep my house 76 in the summer because that is the temp I am comfortable at in shorts. When I go out shopping or dining, I have to wear a jacket indoors. And then the same idiots who keep it at 68 in the summer bump it up to 75 in the winter when everyone is dressed for cold. Go figure.

When I grew up in Texas, there wasn't much air conditioning but when you had it, you wanted to impress people with it. People that just came from outside or inside, in heat and humidity that would murder people that didn't live there.

 

When I grew up in Texas, there wasn't much air conditioning but when you had it, you wanted to impress people with it.

Hopefully they can move beyond that now.

When I visited Shanghai (similar climate to Houston), walking through their premiere shopping area, I was appalled by the practice of keeping the doors to all the stores wide open and using fans to blow cold air onto the sidewalk.

 

I am recalling that the discussion was about failing circuit boards of some kind.
The logical search for a cause of failure will be to look for what is different between the assemblies that fail and those that do not fail. That could be as simple as a different brand of logic IC devices, but it might also be caused by a lack of anti-static procedures during one shift at an assembly plant.
THAT sort of discovery takes a bit of effort to discover. I think that the TS mentioned the failure in the low-voltage portion of the board, back in post #11!
My apology for mentioning mains frequency, which seems to have launched a raging tirade . Perhaps there should be another forum for those.

 

Hi
Please stay On Topic.

Moderation

 

@aspiespot
I understand that you won’t have schematics for the unit, but could you take a good picture of a unit’s PWB?
Additionally, on the failed components, can you read the p/n?
If one of the failures is an electrolytic capacitor, the component’s printed legend should be simple to read.

 

Posts #2,#3,#4, and #5 ask for details about what the failures are. Eventually we get a response as to what TYPICAL failures are, and a statement that these failures sem to be in the low voltage portion of the circuit.

And what I have read is apparently the company is quite willing to tell the unfortunate owners to just buy another control board for $500. That would prompt me to advise all my clients to never ever consider any product from that company ever.

So perhaps it would be time to require an exchange of the failed control board, with enough of a discount to assure that every failed board was recovered. With enough evidence the failed parts and the probable cause could certainly be understood. Knowing the component and the cause should be enough to lead to a solution of the problem.

 

Just a data point on the local frequency stability from my home energy monitor.

The avg seems a little low from 60Hz but still very stable.

 

such as not taking the same anti-static precautions when installing the boards.

The latest issue is with a drum sanding machine and the PCB controls the 90vdc motor. I have checked out all the component's on the switching side and they all seem OK. I'm certain the issue is on the lower voltage side (5v),assume the area which controls the gate on the MOFSET. Sadly trying to find an issue on the low voltage side is way beyond skill level!!! The failures are ALL within the first few hours of use, the PCB just stops working, no bangs ,no burning smells etc

A few observations that may mean nothing to anyone, but on the ESD side of things, It was one of the first things I thought of. Canadian air is dryer due to the colder temperatures. This promotes ESD as a problem that needs close monitoring. On the "Drum Sander" part of this - I operate a custom cabinet shop. When I vacuum up the floors, especially on cold dry days I get a TON of static charge in the hose. That charge is transferred to me, and when I touch the table saw I get a hell of a snap. Gotta be about 50KVS (Kilo Volts Static). The human body can store up to 50KVS. Though when you get the snap it's no longer static - it's a hell of a wholloping current. PCB's in sanding machines are not going to like their environment.

Dust collection tubing is loaded with static; especially if they're not wire wrapped and grounded. I've gotten some good bites from the ABS and PVC plastics used in my dust collection. Without knowing more about the environment the PCB's are in it's hard to tell if ESD is the culprit of more common failures than elsewhere geographically.

A fanciful thought had occurred - the Aurora Borealis. It's present during solar winds. When wind blasts are more direct the Borealis is stronger, meaning there are more charged particles in the atmosphere. It would be interesting to hear if someone in other northern latitudes seem to experience the same phenomena. But like I said, this a fanciful thought, and probably a near zero contributor to the problem.

 

Of course the damage done by a few kilovolts of static might not be instant destruction, but just a bit of damage to the protection diodes of some device. So this is the reason to get back the failed board assemblies to see what parts have failed, and learn why they failed. Often the reason will be rather different from what is guessed by those not involved. I recall a situation where TTL data links were being damaged, and those not involved were certain that it was the inductance of the long data lines. A much closer examination by one who did not believe that found that the panel builder wire twister had left a single loose strand of the 120 volt data line switching relay coil ,not go into the screw clamp, but instead poke up to the next level and contact the data line terminal. All by being lazy and not twisting the strands so that they would all go where they should. There were no huge inductive spikes from the long TTL data lines.

 

Of course the damage done by a few kilovolts of static might not be instant destruction, but just a bit of damage to the protection diodes of some device. So this is the reason to get back the failed board assemblies to see what parts have failed, and learn why they failed. Often the reason will be rather different from what is guessed by those not involved. I recall a situation where TTL data links were being damaged, and those not involved were certain that it was the inductance of the long data lines. A much closer examination by one who did not believe that found that the panel builder wire twister had left a single loose strand of the 120 volt data line switching relay coil ,not go into the screw clamp, but instead poke up to the next level and contact the data line terminal. All by being lazy and not twisting the strands so that they would all go where they should. There were no huge inductive spikes from the long TTL data lines.

Sounds like a job for a bootlace ferrule!

 

This is the reason to get back the failed board assemblies to see what parts have failed, and learn why they failed. Often the reason will be rather different from what is guessed by those not involved.

Yes, fully diagnosing the problem is highly advised. However, the question isn't "why did THIS board fail" it's "Why are boards like this failing MORE OFTEN IN CANADA". [edit: UK]

Have you ever seen a fish bone diagram? For those who may not know what I'm talking about, and it could be the wrong terminology; a fish bone diagram consists of a horizontal line from left to right. Fish bones extend on 45˚ angles from the line up or down to the right. On each line a group of people throw out ideas. At the left is the problem. The bones then are filled in by people saying what it might be caused by. ESD might be one guess. Frayed wires poking to other leads might be another guess. The mail came late. The dog just gave birth to kittens. Could be anything. Then when you've reached a point where there are no more reasonable possible suggestions you start eliminating the worst until you arrive at a few likely candidates. Then you pursue those as possible causes of the failure. Should it turn out that none of the reasonable's solved the problem you then go to the less likely. Obviously dogs giving brith to kittens would probably never even be suggested, but this is how a fish bone diagram works. No possibility is overlooked. Even sometimes the ridiculous. In the end the question isn't "Why did THIS board fail" but again, why are boards in Canada [edit: UK] failing more often than in Sangal or Trinidad & Tobago. Or else where. Why is the failure rate higher in Canada. [edit: UK]

 

Sorry - why do more fail in the UK. Not Canada. My apologies.

 

Rather than random guesses it makes sense to first get hold of some actual failed products, and understand what the result of the failure is, meaning what does the assembly not do that it is supposed to do. (That process requires knowing what the product is supposed to do). Then looking at the circuit and understanding how it works. At that point it will be fairly clear which circuit elements to test. After discovering the failed components, going back to the circuit drawing and understand what the likely cause is. Using this method mostly locates the failed components fairly quickly, and usually provides an adequate understanding of not only what failed but why it failed. It is much faster than most strings of random guesses.
The down side is that it demands that an understanding of the system be possible, and it demands, usually, an understanding of what the problem is.

That is my servicing secret revealed! For those wanting to succeed in the service business, it is the secret path to consistent positive results.