Hayward PS dual voltage only putting out 24v no more 12v

[repair-it]

Can't figure this one out. No shorts. No more 12v out only 24v. This is a power supply for a Hayward salt water control board. Tested everything except for rectifier, transformer and disc caps. I'm not sure how the 12v is generated - I thought it should come from the transformer but all low side wires are grounded. Opto's are working. I looked for a bad transistor/diode on the bottom but no luck -help!

[kaboom]

Re: Hayward PS dual voltage only putting out 24v no more 12v

I see a 5-lead device and inductor & diode near it on the sec heatsink.
Likely a (LM2576?) "simple switcher" IC. Usually with an enable pin- trace that back and see what drives it.

Only 24 comes from the transformer; 12 is derived from that via the buck converter.

[repair-it]

Re: Hayward PS dual voltage only putting out 24v no more 12v

Thank you - Yes, with some afterthought, it would seem the 24v would be sent to the step down regulator LM2596T for the 12v out but it's only outputting.8v. The part that has me confused is that there are 8 wires coming from the transformer 4 on the high side and 4 on the low side. The 4 on the low side are all grounded. Still backtracking, board is covered in urethane coating, slow going.

[farcouet]

Re: Hayward PS dual voltage only putting out 24v no more 12v

Hello,
Have you found the solution? I have the same and also trying to figure out. Really pain to test due to conformal coating and have not found a way to strip it.
Cheers,
Fred