Hi everyone, rank amateur here.
I received this sprinkler controller with a 120VAC input transformer (output being 2x 12v 1A) and didn't notice that it couldn't handle my mains 220V - this is the first transformer I've bought from the US that couldn't handle 120-240V.

Connected the transformer wires to the controller, turned it on, noticed audible buzz from transformer, turned it off. Noticed my error, fetched the electrical meter and a step down voltage converter (for my imported resistive load tools) and tried again, board would not power on.
No-load voltage of transformer is 27V, on 220V mains it's double that, so the transformer still works?

Board has a fuse labeled 'FUSE1'. It's not a fuse that I recognise, the etching on top appears to say '100' and '(Beta symbol)B6'. (see attached image)

It doesn't look like it can be replaced without soldering, is this a single use fuse or something that just needs a while to cool down after it's done it's job?

Any insights would be greatly appreciated! Thanks!

 

Close to FUSE1 there is also a FUSE2. Do you have a multimeter? Check to see of both fuses read (close to) zero ohms.

 

The B is for Bourns who manufacture the component. Looks like one of their resettable fuses. Doesn’t look bad or burnt. Looks like it’s about 1amp.

https://www.digikey.com/product-detail/en/bourns-inc/MF-SM150-33-2-99/MF-SM150-33-2-99CT-ND/3437742

 

The B is for Bourns who manufacture the component. Looks like one of their resettable fuses. Doesn’t look bad or burnt. Looks like it’s about 1amp.

https://www.digikey.com/product-detail/en/bourns-inc/MF-SM150-33-2-99/MF-SM150-33-2-99CT-ND/3437742

Thanks! How do I reset it though? Or does it reset itself after a while?
I read the datasheet but didn't find what I was looking for.

 

Did you check it with a meter? It should reset itself after the fault condition is gone.

 

They reset themselves when they cool down.

 

doubling your voltage could damage components including regulators. Diodes and capacitors. Looks like that fuse is rated for 30v also.

 

Did you check it with a meter? It should reset itself after the fault condition is gone.

They both read 0.5 Ohms, looks like I blew other things on the board then

 

Or does it reset itself after a while?

All the sprinkler controllers I've seen require 24vac input.
What is the no load output of the transformer using the step down converter?
SG

 

might can point out some stuff to check if you can provide some more photos of the entire board

 

All the sprinkler controllers I've seen require 24vac input.
What is the no load output of the transformer using the step down converter?
SG

27 V

 

might can point out some stuff to check if you can provide some more photos of the entire board

 

27 V

That would be correct.
If you are not getting the power LED to come on I would suspect components D2,D3, C23 and even RV3.
Check the resistance across RV3. RV3 looks like it may be a varistor across the AC input.
What's the make and model number of the controller?
SG

 

I'd check the same stuff sghioto just recommended before proceeding further.

 

Not sure if it’s the picture but U6 D5 and the PIC chip looks like it got toasty.

 

Not sure if it’s the picture but U6 D5 and the PIC chip looks like it got toasty.

Those components have a varnish over them, which makes them and the board look dark in that area.

 

That would be correct.
If you are not getting the power LED to come on I would suspect components D2,D3, C23 and even RV3.
Check the resistance across RV3. RV3 looks like it may be a varistor across the AC input.
What's the make and model number of the controller?
SG

Resistance across RV3 is 3.2 Ohms, good or bad?

The controller is a Hunter HC-1200i.

 

That would be correct.
If you are not getting the power LED to come on I would suspect components D2,D3, C23 and even RV3.
Check the resistance across RV3. RV3 looks like it may be a varistor across the AC input.
What's the make and model number of the controller?
SG

C23 resistance is 686
D2 is 669
D3 is 747

 

For diodes you need the diode check selection on your multimeter. Then probe it in one direction and then reverse the probes. It should not conduct in one direction and drop 0.25-0.7V in the other.

If it conducts in both directions it’s bad or something in the circuit may be parallel with it on the board.

 

I usually remove these items when checking them. Slightly lifting one side off of the pad works as well. In-circuit testing doesn't usually give the greatest of results.

The diodes you would want to check how wolframore suggested. The big capacitor I don't think would be bad but you'd want to check capacitance.
This should be data sheet for it:http://www.lelon.com.tw/upload/prod/151003304325.pdf