Greetings; have been a lurker, but this is my first post. Thanks for all the past education I've gained here!

I bought an older Diamonte Grand Canyon with an LX10 controller. The spa worked great for 2 weeks, then the 12V transformer (that supplies power to the digital control circuit) died.

Replaced it and it worked perfectly. For about 6 weeks. Now the new transformer is dead. Spa works fine by feeding 12V (with a battery charger) to the controller circuit.

Before I just replace the transformer again, is there something else I should be checking that may be severely limiting their lifespan? (The old transformer appeared to be original, so it's lifespan was likely not limited...)

Thanks!

Bill
Frederick, MD

Could be a shorted capacitor, rectifier, or possibly a board voltage regulator going bad - drawing too much current from the transformer.

These items are generally not too difficult to replace on the board if you're good with a soldering iron.

What I would do though, is put an ammeter in line with the low voltage output to the board. If it's drawing more than an amp or so of current, then you've definitely got a board problem, and need to disconnect the transformer before it burns out again.

Thanks for the response. My first check was to do just as you suggest. I found the board pulling about 110 mA with the pump not running and about 150mA running in high speed (no difference running in low).

I did not think to test it with the heater running and/or the light on (because the light is very rarely used)... do you think the heater being on could add significant load to the control circuit?

Not knowing what the specs _should_ be, I didn't think the 110-150mA was extraordinary.

Thanks!
Bill

You were measuring the current on the primary side of the transformer.

I was referring to the secondary.

But 150 milliamps on the primary is significant. 120V * .150A gives 18 watts.

Most transformers of this type are rated around 24 watts - (200 ma @ 120 V).

The more relays are energized, the more current is being pulled from the transfomer. I'd definitely get some readings with the heater running, that'll add 2 more relays to the mix.... then with the jets, etc.

Actually, I thought I was measuring the secondary side. Specifically what I did was hook my ammeter to the battery charger than I'm using to feed 12V to the control board in lieu of the transformer (which is unhooked altogether).

I'll try to measure the same with the other things running.

Thanks!
Bill

You should never use a battery charger to do the testing with. Those things output pulsed dc, and you will not get an accurate reading - (plus could kill the on board power supply as they are poorly regulated). You should be checking ac amperage directly in line with an ac transformer.

Actually, I thought I was measuring the secondary side. Specifically what I did was hook my ammeter to the battery charger than I'm using to feed 12V to the control board in lieu of the transformer (which is unhooked altogether).

I'll try to measure the same with the other things running.

Thanks!
Bill

Yes I've acknowledged that you are.

But a battery charger in line will not give you correct amperage readings due to the fact that most of them output pulsed dc, not ac as the circuit board power supply expects.

You really need to be measuring AC current draw, with an AC transformer input to the board.

The circuit board should draw a good deal more than 100 MA (at the secondary) when powered up.

Sorry, not sure how the double post happened.

I apologize for my basic questions, but my electrical skills pretty much end at 12VDC.

The transformer appears to be powered by 240VAC from the circuit board and feed 12VDC back into the circuit board, all in a common plug.

What I had done as a test was to unplug the dead transformer and supply 12VDC from a battery charger into the board at the same place the transformer was supplying it. I was able to measure the DC amps that I was feeding in.

For further testing, I will replace the battery charger with a regulated 12V supply (from an 110V AC transformer). Again I will be able to easily measure the DC amps that I'm feeding in.

Where specifically do I measure the AC Amps? Where the 110V transformer plugs into the wall?

Thanks again for the assistance!
Bill

Update:

I replaced the battery charger with my 800mA power supply.

DC draw was measured as before with 110mA DC with the unit powered up, 150mA with the pump running... and pegged out my 250mA gauge when the heater kicked on.

However, no real voltage drop with the heater running AND the light on, so I think the total draw is well under the 800mA my power supply was capable of putting out.

Bill