Irritrol–RD1200 Sprinkler controller repair

I always have issues with water, I’ve flooded a couple of houses over the years. So the new house’s sprinkler system is no surprise, we have almost 150PSI of water pressure going into an old metal pipe sprinkler system, and I’ve been slowly replacing the pipe and reducing the pressure under concrete and all that,. This week i noticed a large dome shape on the front lawn and it turned out there was a few hundred gallons of water under the turf, and another broken pipe. Also the new flowers I planted had started to die off while I’d been out of town. the people I’d used to replace some of the bad pipes had missed one sprinkler output which had covered these flowers, so it goes on. I went out to repair these and I noticed the sprinkler solenoid  was chattering. 

Checking out the rest of them, they were all chattering, so its obviously a problem at the controller and not the solenoids. I checked the output of the transformer, about 26VAC, so that was fine, watching the sprinkler output it was swinging from about 6VAC to 18VAC, when it hit 12VAC or so the solenoids would chatter.

So I opened up the control box. Remove, power, Remove the ribbon cable, me plastic tabs that just pop out, then two screws hold the PCB down, which keeps the flexible LCD connector in place.  it just lifts out after the screws are removed.

 

A few minutes inspection revealed the issue.

 

The electrolytic capacitor is slightly swollen and leaking, its a 220uF 35V axial style, radio shack carries them for about $1.40. Changed it out and  its all working again, but make sure when you reassemble the box that the ABC switch gets on top of the PCB mounted switch, otherwise you’ll be doing what i have to do tonight and take it apart again.

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