Irrigation controller repair

[ht23]

Hi Guys,

First time posting for anything so fingers crossed on some advice. I have an irrigation controller that I had installed a number of years ago but have not used due to all the water restrictions. It is based inside my garage so not in the elements. Everything seems to work fine but it turns it self off after a short time ie from 15 seconds up to a minute. I have tried to run it from mains power and battery back up and even disconnected all the solenoids to isolate any problems but I get the same result. It seems like a new product due to the amount of use so I don't want to replace unless necessary and it feels like it would be a basic repair for anyone that understands the electronic components.
Any advice much appreciated before it hits the scrap heap.

Thanks

 

[davenn]

hi
welcome to the forums

tis a bit difficult to offer any advice since you have given no info on the controller
how about the make and model and any links to info on the unit
then how about some pics inside and outside of the unit

cheers
Dave

 

[ht23]

Hi Dave,
Thanks for quick reply. I thought I could get a generic reply but I will provide details and pics as soon as I get home. Wasn't being lazy just new to this stuff. Look forward to your advice. Regards Harry

 

[ht23]

Holman 8400 Irrigation Controller

Hi Again,

Ok, I think I have attached images. The unit is a Holman 8400 irrigation controller. All the solenoids work ok and even when they are disconnected the unit turns off. Whilst it is on everything functions so being someone who knows very little about electronics could it be something to do with the power supply????!

Thanks in advance for assistance.

 

[KrisBlueNZ]

Hello Harry and welcome to Electronics Point

I found Holman Industries' web site at http://www.holmanindustries.com.au but there's no mention of an 8400 model. I guess it's obsolete now.

My first thought is that it thinks there is a problem and is shutting down as a safety precaution. Read the manual carefully to see whether there is any feature like that.

If not, you'll probably have to start by taking the covers off and posting some pictures of what's inside. I have never seen an irrigation controller, and I doubt anyone else on the forum is familiar with them, (but you never know...) so we'll probably need to start from the ground up.

What test equipment do you have? A multimeter?

Also check the circuit board and connectors for signs of damage from moisture or salt. It may be a good idea to scrub the board with a toothbrush and soapy water then let it dry thoroughly, and try again. Leakage paths can cause odd behaviour like this. But upload some photos first.

 

[ht23]

Irrigation controller

Hi Kris,

Thanks for your welcome and reply. I couldn't find anything relevant in the manual and the manufacturer weren't very helpful when I called. I have taken the unit apart as per the photos and everything looks very clean. Not even a spider web which is what I expected to find.
Just a bit of extra info, there are 15 solenoids which wire into where you see all the screws along the blue plastic strip.

Unfortunately I don't have a multimeter. My only electronics tools are lots of cables, connectors etc

Sounds like it might be more complex than I'd hoped. I just thought I'd try my luck for an obvious fix based on what is happening.

I'm open to any suggestions and thanks again.

P.S. I will post pics separately as I'm having trouble uploading. Probably due to file size.

 

[ht23]

More pics

 

[ht23]

One more

 

[KrisBlueNZ]

As you say, it all looks fine. Here's one suggestion though. In the bottom right corner, the red component above the right hand end of the fuse is a "PTC fuse". Power up the unit with the front cover off, wait for it to power itself off, and see whether that component is hot or not. If it's hot, it will be pretty hot, so be careful not to burn your finger!

 

[ht23]

Hi Kris,

I tried what you suggested. It was not hot .... at all.

Thanks for your effort.

 

[KrisBlueNZ]

Ah well, it was just an idea.

Could you upload some closeups of the front side of the board so that the IC part numbers are readable...

 

[ht23]

Hey I just looked up the time in Wellington. I appreciate your determination but get some sleep ! This has been a problem for a few months now. I will upload pics one at a time again and reply when you get a chance.

Many thanks

 

[ht23]

More pics

 

[ht23]

More photos

 

[ht23]

Photo 4

 

[ht23]

Final photo

 

[KrisBlueNZ]

Hmm. I don't think it's gonna happen. There's nothing visibly damaged, and no components that are easy to test or likely to tell us anything, apart from the PTC fuse which you've already checked. If you bought a multimeter, you could check the supply voltages on the microcontroller, the output driver ICs, and the regulator, which might tell us something, but it might not.

What do you think?

Edit: You can also check the regulator for overheating. It's the black transistor-like thing on the right side, about a third of the way down, between the blue electrolytics that are sitting flat against the board. When the board has turned off, see whether it's hot.

 

[ht23]

Hey Kris, I have checked just about everything for overheating and everything seems ok. I really appreciated your help but I think it might be time for a new one,
All the best.

Harry

 

[KrisBlueNZ]

Fair enough. Disappointing, but... you win some, you lose some, I guess

 

[Jagtech]

I recently had a Rainbird controller that acted similarly. It turned out to be electrolytic caps in the power supply circuit had gone bad from age. Just a thought.....