Got expensive replacing batteries in my Rat Zapper Ultra. It is very sensitive to battery voltage sag, and will begin rapid red led flashing when batteries get a even a little low, i.e. 5.8 volts (4 d cells) will cause flashing. So batteries don't work very long.
So I decided to "wire" it up for a plug in wall wart power supply. I had a model AD-0660-ul, 6v DC, 600mA output power supply with correct 1/8 mini headphone plug (mono 2 conductor) on it. Note that the zapper needs more amps to run the zap, so I will have to find a supply with more output...around 2000mA should do it.
To wire the Rat Zapper I re-purposed the existing jack on the top of unit designed for the "Rat tale" indicator accessory. If you want, you can add another jack of your own choosing, and that will allow you to use whatever 6v supply you have on hand and you can just match the jack. While leaving "Rat Tale" jack functional.
The wiring was easy. The existing jack has a black and blue wire attached. Black is ground, so just leave it. The blue wire is for the "rat tale" so I cut it 1 inch above the pc board connection ( leaving a section long enough to reattach If needed later for "rat tale"). Next I melted a small section in the middle of the Red wire going to pc board connector that feeds the batt power into board. I then twisted blue wire from jack around red exposed wire and soldered. a bit of hot glue around joint and against side wall nearby to insulate. All done. So that's it, just one connection change and you're ready to zap battery free.
Try not to unplug power with the zapper switch in ON position. The circuit doesn't like it and the unit will not power up for a while, but it will revive.
No this is not sanctioned by maker, thus voids warranty...if there is one. Has not been UL tested and maybe hazardous in some way, so try at your own risk.
Good luck Zapping and saving on Batteries.
SteveSparks