No Voltage on stations when the station is turned on

[cphgsales]

I have an opensprinkler pi that the led is illuminated which I have assumed to mean its getting power but I can not get 24v on any stations when the station is turned on.
<div style=”color: #222222; font-family: arial, sans-serif; font-size: 12.8000001907349px; line-height: normal;”>It was working fine until a sprinkler valve actuator/motor shorted from corrosion. I replaced the valve actuator/motor and rebooted but now none of the station have power when activated.</div>
<div style=”color: #222222; font-family: arial, sans-serif; font-size: 12.8000001907349px; line-height: normal;”></div>
<div style=”color: #222222; font-family: arial, sans-serif; font-size: 12.8000001907349px; line-height: normal;”>Is there a troubleshooting guide?  anything obvious?</div>

[Ray]

The first thing to check is the fuse — it’s a small cylinder tube shaped fuse. Check if it’s blown. You said the LED lights up, so the fuse is likely still ok. Next thing to check is to see if there is any visible component damage on the circuit board.

[pb]

How are you checking the voltage?  If you are using a multimeter make sure it is set to AC rather than DC.

[cphgsales]

I’m sorry I meant when the station is activated via mobile application there is no change in voltage (24 v ac is not detected). I’m assuming there is no type of protection for a short when an expansion board is connected and I suspect that the shift register, processor or something fried even though there are no visible signs of component failure.  This all started when I had a solenoid stick on and possibly short  a station connected through the expansion board. The end result is now a mystery, more specifically why none of the stations are working.  I think this is unfortunate because sprinklers solenoids are often exposed to moisture from flooded sprinkler boxes, busted sprinkler heads and leaking valves. If a short from a flooded sprinkler box or solenoid failure causes  a complete component failure, I can’t see these boards lasting very long in a real time environment.  These terminals need some type of protection from corrosion and shorts because its not a matter of if but a matter of when one of these situation presents itself.  I am going to send the board back to see if Opensprinkler can figure out what happened.

[Ray]

Are you running Dan’s interval program or Rich’s sprinklers_pi program? Rich’s program disables the station output by default, I think, and you need to go to settings to enable it first.

[Ray]

Speaking of protection: all OpenSprinklers have built-in fuse (two of them, one for 24V AC line, one for 5V line), zener diode, and per-stations transient voltage suppressor. We’ve integrated most protective components we can think of. Of course these won’t prevent all kinds of damages, but I don’t think the circuit protection is any worse than other commercial controllers on the market.

[cphgsales]

Ray,

Thanks for the response. I mailed the two items back to you so that you can check them out. I’m really not sure what could have went wrong ?  If it was a power surge, I would have expected a fuse to pop but the LED is illuminated.   Maybe a processor is bad or shift register. I’m not sure how to check these items out. Hopefully your more familiar. Let me know what you think when you get the unit back.

[Ray]

Received your package. After checking, it turns out that the shift registers (all three — one on OSPi and two on expansion board) are all damaged. This is quite rare because the shift registers are usually very robust. I can’t think of a good reason, the fact that all three are damaged probably implies some sort of over-voltage situation. It’s also rare that the shift registers are damaged but the other components are fine (fuse, triac). When there is a shorted solenoid, the fuse may break, or triac may be damaged, but I’ve never seen shift registers damaged, particularly with no other components damaged.

My only suggestion is that when plugging in the expansion board, make sure to power off everything before connecting the expansion board. ‘Hot’ plugging in can be a potential issue. Anyways, I’ve replaced the shift registers and made sure both have passed functional test. It will be shipped back to you tomorrow. Thanks.

[cphgsales]

Ray,

Thank you for looking into this and doing so in such a prompt manner.

[Author]

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