Teardown And Restore Of A Insoma Water Timer

Water timers are nifty gadgets that may water the garden at set occasions or hold that vegetable backyard from turning right into a dustbowl. When [electronupdate] timer refused to output water on any of its three shops, he did the fitting factor. Instead of angrily checking the guarantee on the sodding factor, he tore it apart to attempt a repair.

As anticipated, the design of those gadgets is kind of simple. Three solenoids management whether or not an outlet is open or closed. A management board additionally handles the consumer controls and show.

There was no apparent signal of injury, and the PCB was potted in a white substance that ought to have saved out any moisture. A fast verify with a battery revealed that the three solenoids additionally labored simply advantageous, so the trigger doubtless was someplace on the — potted — PCB.

These solenoids are rated for 6VDC and take about 20 ms to behave, however on an oscilloscope seize it was plain to see that the board was solely placing out round 2V. This wasn’t sufficient to drive the solenoid, elevating the query of what had gone mistaken on the controller board and setting the stage for some enjoyable epoxy potting compound scraping.

A superb little bit of elbow grease revealed the management ICs, the H-bridges that drive the solenoids, and the remainder of the circuitry, together with an influence enhance circuit with an enormous electrolytic capacitor. The latter had a little bit of suspicious liquid close to its base, which turned out to be the wrongdoer. Perhaps essentially the most annoying factor right here is that this electrolytic capacitor had the temerity to fail after solely 4 months of use, however at the very least it was a simple sufficient repair.

If we had been in there, we’d have been tempted to keep away from many future battery changes. Impractical, however we marvel if anybody ever constructed a water timer with a water clock?