Replacing an Unusual Power Supply

I have spent a lot of time fixing this inflatable display this year, and I am not about to give up now. Last year, I had to make an emergency repair to the A/C adapter after this snowman lawn decoration blew away and tore the prongs out of the plug. That repair lasted a year, but we had one heavy rainstorm last week and water got into the adapter causing it to short out, so I have to make another fix to get it going again.

For the last week, I was working on another fix to replace a faulty LED board in one of the snowmen. That fix worked great, and continues to work when it has power. After that fix, I have too much invested in this thing to let it die.

The white cord poking out of the electrical tape was a quick hack job I did last year to make this thing work. After strong winds blew the snowmen down the street on the first night we had it, I had to repair the missing prongs on the adapter. I pried open the plastic case of the adapter so I could see what I could do. I cut a cord off a broken fan I was throwing out and soldered the wires to the loose leads in the A/C adapter. That fix worked for all of last year's Christmas season and most of this one.

The other day, I came home and the snowmen were not inflating or lighting up. I took a closer look and they were flashing slowly off and then on briefly. There was clearly a short, so I unplugged the adapter and brought it inside. I could hear the power supply sizzling while it was plugged in. Once I opened up the case, I could see the scorch marks on the circuit board.

Unfortunately, there was no repairing this power supply, but I could reuse the only part that would prevent me from using another 12v adapter.

The only part that I couldn't make or replace was the unique threaded connector that received the plug from the lawn decoration. Without this piece, I would have to cut the plug off the snowman wire and splice in a more universal connector.

Inside of the power supply, all of the empty space was filled with some black sealant. The sealant was somewhere between a wax, silicone and hot glue, and it made a mess on my hands and the knife I was using to remove it.

Once I freed the wires from the sealant, I cut them as close to the board as possible so I could reuse them and make a universal adapter.

I used the adapter that I made from scrap pieces in this guide to make a more permanent solution to power the 12 volt circuits inside the inflatable. I took the threaded power jack from the snowmen power supply and stripped the insulation off the 2 wires so I could fit them into the screw terminal. The adapter is just a small piece of perf board scrap, a 2 pole screw terminal and a 5mm female connector.

The power supply I am now using is from an old scanner and it has a standard 5mm barrel jack connector. I keep it around because I use it for Arduino projects and it works great. It seems like the wattage is lower than the power supply that the snowmen came with, but they light up and inflate as I hoped. The inflation may take a little longer than normal, but I can live with it. This is an indoor power supply so I have to keep it and the adapter I made in a little plastic container to keep the water out.