Hi,
Fellow newbie here!
Bought the same tank today and I now have the same problem.
For information, I *think* the problem is a blown capacitor in the switch unit.
I've done some research online, and got the toolkit out.
Firstly .. this is low voltage kit! However, please don't try this at home kids unless you are with a responsible adult!
The tank lid takes a 15V AC input, which outputs two sockets. One for the filter/pump and one for the switch unit.
The pump works in both sockets, so power to those is fine.
The switch unit appears to convert 15v AC to ( I assume ) 12v dc for the led strips, as that's what the interpet units appear to run on, and they look identical.
Plugging a led strip into the 15vac outlet ( not recommended! ) sets them to flash brightly, seeming to confirm the above.
Taking the switch unit apart there isn't much to it. Just a largeish heatsunk transistor, a couple of caps and the switches and resistors. It's unlikely that the resistors or transistor have gone, which leaves the 470uf/25v caps. Caps *do* blow
The 'monthly reminder' unit that *also* plugs into this works, but the led lights are a lot dimmer.
All the above is conjecture, but it makes sense to me.
I *may* just manufacture my own led power sources from the gazillion of transformers in the loft. The inbuilt switches won't work unless I re-solder my stuff onto them but hey .. I can live with that!
I don't think I can be bothered to drain it all and take it back. I've already been back once to exchange a smaller (and faulty) tank for this one, and the staff at pets-at-home were actually super helpful for the record.
Anyways, sorry I don't have a solution, but you're not alone !
Going to leave the tank for a couple of weeks to settle. First fish tank for us, so we need to do some thinking on what we're going to put in there
Take care!
fdm