OpenSprklinkler v2.1u Power Switch Failure / Burnout

[colinsfl]

Hi All,

I’m hoping that someone can help with a problem I have with an OpenSprinkler v2.1u PCB that died the other day.

Essentially the NS LM2596S-5.0 failed and burned out, but the fuse is intact and not blown. There is a crack on the lower left side and the plastic shell is burned and pin 1 [V-In] is very discolored as though it’s been heated up. The AC power supply is a Hunter WT57 26VAC 750mA power supply that measures as actually outputting 29VAC. I read somewhere that the WT57 is compatible with OpenSprinkler so I’m assuming that the extra AC power supply voltage might not be a problem, but I don’t know for sure if the board can handle that or not.

Details of the installation:

1. Replaced a Hunter SRC – 6 Station Controller.
2. The Valves are an unknown make because I got them with the house and don’t know where they are located exactly but they worked fine with OpenSprinkler for a while without problems.
3. The Sprinklers are all Hunter PGP type.
4. There is a rain detector connected. This is a simple switch type detector at guttering height.
5. The OpenSprinkler is situated in a non-air conditioned single garage in Central Florida. We get regular thunderstorms most days and heat around 95 F in the sun during the summer, there is no freezing in winter. I’ve not measured the temperature in the garage but I can if it’s relevant.
6. The Ethernet was provided via a homeplug, but because there was only one port I had to use a spare Netgear Switch which was a GS605v5. The OpenSprinkler was connected to that Ethernet switch as was a POE adapter for my external security camera.

So the problem I have is what I need to do to fix the OpenSprinkler [if possible] and also try to ensure that the problem does not reoccur. The trouble is not only the OpenSprinkler is fried, and that’s where it gets a bit complicated. The Netgear switch is totally dead, the POE adapter Ethernet [Data In] port is dead but the POE port seems fine, the security camera is fine, the HomePlug Ethernet port is fine, I’m hoping that the OpenSprinkler Ethernet Port also survived. My working assumption is that the POE adapter failed and caused the Ethernet switch to die and then that in turn caused some kind of an issue on the OpenSprinkler, perhaps an over-current on the LM2596S?

So I have a couple of questions for anyone that can help me.

1. Is the 29VAC output from the Hunter WT57 fine, or is it a problem?
2. The only visible damage to the OpenSprinkler is the charred LM2596S. I’m thinking that replacing that will fix the essential problem. In the meantime as that part is only for creating a 5V DC supply, where on the PCB could I connect a 5V DC power supply just to see if the OpenSprinkler is OK, or perhaps run it temporarily off an external 5V adapter?
3. I decided to get a 2-port Home plug and remove the cheap Ethernet switch from the mix just in case that was the actual cause of the problem and not the POE adapter. I’ve also ordered a replacement POE adapter. Does anyone have any experience and advice to offer on this Ethernet setup?

If the OpenSprinkler is not repairable, then I’m thinking of getting the OSPi but I’m a bit worried that the heat in the garage is too much for that solution. However I could possibly extend the wiring into the utility room which is air conditioned in order to reduce the temperatures, but there is no convenient power socket so it will be a big job and I don’t know if heat is a real issue here. It’s probably only at most 35 C ambient air so it ought to be OK but the OSPi case does not seem to be ventilated anywhere therefore heat will build up over time.

Thanks

Colin

[Author]

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