Since it seemed that it was related to the door, I started looking around the interlock.  The interlock on a microwave does several things.

• It turns on/off the light inside of the microwave.
• It stops the turntable if you have one when you open the door.
• It prevents you from running the microwave with the door open.

It  is this last thing that is the most important.  You are not going to glow in the dark if exposed to microwave energy.  It is non-ionizing radiation.  It is more like a powerful radio transmitter.  But if the interlock failed and the oven was still running when you stuck your hand in there, it would not be a good thing.  1000 watts of microwave can heat a popcorn kernel to over 400 degrees in a few moments.

So, where was I…  the interlock.  On my microwave there are a series of microswitches along the front and back of the interlock mechanism (4 total in my particular model)  The mechanism is held in with only 2 screws, so it is pretty easy to remove.  Somewhere on the inside your microwave (once you get the screws off and remove the cover) should be an envelope with a wiring diagram of how it is all connected.  But just to be sure, grab your camera and use the macro(close up) settings on your lens to get some close up shots of how the wires are connected to each switch before you start taking anything apart.

The microswitches are fairly easy to remove.  They are simply held in with some plastic tabs.  Be gentle, you don’t want to snap any of the tabs off.  In my case, it was pretty obvious which switch was bad.  It was a simple game of “One of these things is not like the other ones”.  On one of the switches the little plunger on the top of the switch was stuck down inside the body of the switch.  The plastic shield around the lug that attached the wire to the switch was blackened on the inside, and the lug on the switch was discolored like it had been overheated at some point.  When I removed this switch from the interlock, it fell apart.  Inside the contacts were clearly charred where some severe electrical arcing had occurred. 

My guess is when the plunger became stuck in the switch body it caused a dead short when the door was either opened or closed, thus blowing the fuse.  There is a set of  upper and lower microswitches that work in tandem to detect that the door is properly closed.  Activating one, must have caused the dead short in the other since it was stuck.

A trip to a local electronics supply house provided me with a plethora of replacement options.  I chose a nice Cherry microswitch with the same dimensions and ratings.  It was simply a matter of paying $1.25, sliding the new switch in place, reconnecting the wires, and installing one last replacement fuse.

I am happy to report that it has been several days, and several cups of tea later and it is still working fine.

Never attempt this type of repair if you are not comfortable working around electricity.  And Never Never plug in the microwave with the cover removed.  You do not want to energize the magnatron (that big metal thing with the metal fins that heats the popcorn to 400 degrees in seconds) with the cover off.  The inside of the microwave also has a couple of fairly large capcitors that would curl your hair, in a bad way, if you poked at the wrong thing.  This is also clearly going to void your warranty if you have one.

I already have curly hair (What’s left of it) and have always been perfectly at ease taking things apart.  This repair saved me about $500 -  The cost of a replacement microwave + a new trim kit.

My weather station is back online.  About a week ago, a friend of our neighbor was over and he just happened to be one of the senior meteorologists for the NWS in the Bay Area.  Speaking with him was the kick in the ___ that I needed to dig into the server and software to get it back online.  The weather to the right over there is from my own weather station.  I have been an amateur weather geek for quite some time.  I am not certain why.  We only have 3 seasons in California – Green, Brown, and Fire.

I have been running my own weather station since about 1999.  I was tired of the weather reports for our area coming from one of 2 airports about 30 miles away.  Neither was accurate due to the bay and coastal influences, and micro-climatology of the area.  The weather sites would report a high of 90, and we would be roasting at 102.  Or no rain would be reported when my own backyard gauge would be half-full.

My first weather station was a Dallas 1-Wire kit.  The station was a proof of concept design to promote the capabilities of the Dallas 1-Wire data chips.  It was a very cool system, and was very reasonably priced.  There was a temperature sensor, wind speed and direction, and an optional rain gauge.  The DIY weather community took this initial offering and ran with it.  In short order there were all kinds of sensors available to order as kits, or you could etch your own boards.  Humidity, solar UV, leaf wetness, and solar luminance, and lightning detectors are some of the sensors that were available through the DIY community.  Maxim Semiconductor bought Dallas which discontinued the weather station.  AAG now sells an improved version of the original kit.

The problem with the 1-Wire system at the time was reliability.  I am not an electrical engineer, but from the common complaints it seems that maybe proper grounding or shielding may have been an issue.  Nearby lightning would often take out sensors.

After having a couple of my sensors stopped working and with the expense and time it took to replace them, I decided I wanted something a little more reliable.  Enter the Davis Vantage Pro 2 – Wireless…

The Davis VP2 has been a very solid and reliable station.  It is solar powered.  It transmits the data over a wireless connection to a very nice display panel in the kitchen.  But I also have a Davis Wireless Envoy (A data receiver without the display) in the near my server to collect data and create my weather pages and upload my weather data to Weather Underground and Citizen Weather Observer Program, or CWOP.  This data is used by the NOAA National Weather Service for research.  My station was the second personal station registered with Weather Underground for this area.

The software I use is WView which runs on a small linux server in my home.  The software used to be a nightmare to configure and get running.  But it has improved greatly.

Thanks for stopping by…