Irrigation Repair 101

Third in my series of home repair items ... the rain sensor for my irrigation system. The function of the sensor is to detect rain - and then inhibit the operation of the irrigation system for a period of time, so that the system is not on unnecessarily.

It had needed to be relocated from it's old position - and as part of reconnecting it, I though I'd test it as well.

Unfortunately, it didn't want to work in the new location. Rather than buy a new one, I thought I'd open it up and see what the problem could be.

They are quite simple devices ...

• a sensor, which consists of a number of fabric type discs stacked on a rod
• when the discs are exposed to water they expand
• which in turn presses a micro switch

I disassembled the unit - and tested the micro switch - which was all ok. This particular one has the three leads: 

• one common
• one for a normally open circuit
• one for a normally closed circuit

This picture shows the bottom of the pole protruding into the chamber which houses the micro switch.

The discs themselves also seemed fine. I gave everything a clean, and reassembled.

And here finally is the result - the irrigation controller showing the rain symbol.

I can only guess that the process of relocating the sensor disrupted it in someway. But, a working sensor makes for a happy gardener.

Door Chime Repair 101

Following on my theme of repair, rather than throw away and replace ... my attention turned to my door chime - which had not been working properly for a while.

It's a simple model - an Arlec DC371 - $35 retail. After changing batteries in the receiver and transmitter, it was still not cooperating. But, in looking around inside the transmitter, I inadvertently pushed the button to select the tunes - and it sprang in to life.

So, I knew we had some basic functionality. I returned to the circuit board, and inspected the main micro-switch for the pushbutton. It had two leads protruding from the other side of the circuit board - so I shorted the switch output with a screw driver, and hey presto - it worked.

The cuplrit was the micro-switch. And they don't call them micro for nothing.

It looked a little daunting. The top plastic retainer was fixed by 4 little plastic lugs. I sliced those off, and underneath was a small plastic button, sitting on top of a flexible metal disc - which was slightly convex, so that it clicked when depressed.

Under the disc were 3 contacts - two at the sides, and one in the middle. When the disc was pressed, it closed the circuit between these contacts. I removed the disc, and tried shorting the contacts with a screw driver but this didn't seem to work.

I gave the contacts and the disc a good scrape with a sharp knife, and a clean with some vinegar. And this seemed to be enough to allow the contacts to work. Result.

The tricky part was re-assembling the switch, since I'd cut off the tops of the lugs. I turned to my trusty super glue - but the first attempt failed - since it seemed to find it's way in to the mechanism.

I broke it down again, cleaned the parts, and tried again. This time was successful.

So, it's now back in operation. No more complaints from family and friends that the door bell isn't working.

I know I could have bought a new one ... but it's the principle, right?

Toaster Repair 101

Dualit Combi

This is the story of one of my favorite kitchen appliances ... my Dualit toaster.

It's a Combi 2+1 model, and has given almost 20 years of faithful service - until the other day when the centre element shorted and died. Needless to say, it caused a bit of a calamity in our household. I've had it since the early nineties, when it was received as a gift from a wonderful friend in London.

Fortunately, I’ve long known that the simplicity of it’s design is one of it’s virtues. No electronic circuits. No fancy lights or displays. Just a simple mechanical timer. And most importantly, nearly all of the internal parts are user serviceable. I turned to Google in the first instance but was surprised to find no local distributor of parts in Australia.

But I did find what seemed to be a fairly reputable distributor with quite a shop front on EBay in the United Kingdom. I downloaded the instruction manual as a PDF document - which illustrated how to access the slots which hold the toaster elements. And how to replace the elements as well. This also showed the simple coding scheme which allowed me to match up my broken part with the appropriate replacement. I placed the order (which was around 20 dollars) and received it about 7 days later.

Inside - showing slots

I needed to wait until the weekend to find the time to devote to the replacement process - which is ok, since that’s when our major toasting happens.

I'm pleased to say that the operation went without a hitch.  The only issue is that the centre element is more efficient than the sides, leading to a slightly less even toasting result - perhaps I should have ordered replacements for all of the elements at the same time.

But, it does make you think. The fact that this and many other parts could be replaced didn’t happen by accident - it was designed in.

It also reminds me of an article in the New York times I’ve read recently, which highlighted a concept of ”Repair Cafes” in Amsterdam. The article is here: http://www.nytimes.com/...

These are places where members of the public can bring broken appliances and a team of volunteers attempt to fix them. What a great idea.

Imagine what could happen if we had products which are designed to be repaired - and communities to help support them.