I retired from the appliance industry after 20 years. One thing that really bugged me was our design teams constantly repeating mistakes made years before. There existed a requirement stating that before an individual could move into a new position, he or she had to serve in the current position for at least 18 months. This may sound like a long time but in the design world, you are still considered a "new-be" after 5 years. With the exception of a fairly small team of designers, there was constant turnover. I know this contributed to the dumb mistakes made on a fairly continuous basis.
The redesign by the Chinese manufacturers is pretty common. It's pretty common here in the US. I just went through the same BS on my project. To test out this company I sent them solidworks models for two fairly simple plastic plates to make. I should have had the parts back within 24 hours. What I got back first was an email with a pdf drawing of the part and saying they would have it done by tomorrow. What they did was decide the holes threads and recess should be changed regardless of the fact they had zero idea what each were there for. So this drawing showed missing fluid passages, mount holes, holes that were re-sized or moved. I politely sent him my remarks basically telling him to "unfix" it. It's over a week later now and no sign of these. My experience with Chinese manufacturers is you can count on your product being exactly what you want right up to the point you drop off the drawings. Then they go work with cost reduction and resulting quality erosion. This is an on going thing and even if the first units are perfect within a year the quality will worse.
In aerospace we saw this all the damn time which is why we had to have QA almost 100%. In frustration we started putting MIL-TDP-41 as the mandatory manufacturing spec to follow. If someone asked us what that was at least we knew they were looking at the plans. That stood for "Make It Like The Damn Plans For Once". We stopped that when some of our shop drawings made it up to much higher federal types who reside at some cape in Florida. They actually thought it was great and had a good laugh. However our boss had shall we say a royal cow/meltdown and in no uncertain terms said not to do it again. And we never did (sort of, maybe ;-])
Back in the old days when microwaves used RF gaskets to contain the RF, Radio Shack sold microwave leakage meters. I still have one. I tested my microwave with it a while back. Only at one corner of the door would the needle even move a tiny bit off of the zero pin.
Since the mid 70's (I think) microwaves have used a clever RF choke in the door to contain the energy. Unless the door is damaged, it will not leak. However, you can't completely contain all of the energy and modern RF electronics is extremely sensitive. IMO, it's impossible to stop the interference and I believe that the leakage from the microwave is well below the unsafe level.
Yes. The cordless phone whacks out big time when it is close to the working microwave. Even if I'm about 15 ft away, it breaks up and the display goes out. If I recall correctly, the microwave runs at 2.45GHz. According to my owner's manual, the cordless phone ranges in frequency from 2401.056 - 2481.408 MHz.
There is really nothing I can do about it. I'm not going to trash my cordless phone. I just don't use it while the microwave is on. My Wi-Fi enabled Squeezebox internet radio and my RF link between my laptop and my audio system also break up when the microwave is on. All microwaves run at the same frequency, so there is nothing I can do about it. All of these devices have an FCC message printed on them or in the user manual that they must tolerate interference from other devices, and suggests that I relocate it to minimize the interference.
The Inverter was a replacement for a Little Litton microwave that I bought in 82 (yes, 31 years ago). It started haveing door interlock problems and was getting to be a real pain. I payed $120 ('82 dollars). The Inverter cost $80 a couple years ago. The irony is that after I put the Litton aside, I must have bounced the junk out of the interlock switch and, naturally, it started working again. It now gets used to warm up the coffee or as a second cooking timer. 31 years, how long with the Inverter last?
@OLD_CURMUDGEON, We also ask if the company logo on the device is counterfeit. I would like to ask Andy Morris to see if a cordless phone works while he stands next to the micorwave oven. They both work on the same 2.4 GHz frequency. If the phone has problems, get away from that oven and trash it.
TJ, that is a terrific idea. Occasionally a manufacturer will find the posting and begin a conversation with commenters. Sometimes, the person posting the Monkey blog will alert the manufacturer that discussions are proceeding. Sometimes the manufacturer jumps into the discussion, sometimes not.
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For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.