Quoted from HappyHarold:
Can anyone suggest a better way to connect (and then protect) two wires to a third wire? As the photo shows these wires have been twisted, soldered, and covered with electrical tape (which I've removed for the photo).
Would it be neater and more secure to use splice and heat shrink, inline connectors - inserting two wires in one side and one in the other?
If so, since these are 18 gauge wires, what size inline connector do I need? I presume one that fits 18 to 22 will be too small to handle two 18's on the same side. Does this mean I need something like a 14 to 18 (if that even exists) to handle two 18s on the same side and an 18 on the other?
These wires come from the transformer and get plugged into J115 on the power circuit board on my Williams Funhouse.
Is that actually how it came from the factory? Seems unlikely. I'd try to find out what a factory install looks like and match that.
Barring that, what you really have is one wire going to the connector, and a second one tapping off it. Instead of attempting a three-way splice, I'd fix the wire going to the connector so it goes straight there without a break. Then strip a gap in the insulation at an appropriate point back, wrap the second wire around it, then solder it and heat shrink it.
Don't forget to put the heat shrink on the wire before everything gets hooked up, and make sure you use tubing (just) large enough to accommodate the double wire.
Another option are Wago connectors (maybe that's the inline connector you're referring to). Wago makes a variety of options (and of course there are knock-off versions). For stranded wire, I'd go with the lever nuts, which I guess is their bread and butter.
I know you didn't suggest it, but I definitely would not use wire nuts. Even the Wago connectors seem a bit questionable a choice to me, but if I ever saw a wire nut inside a pinball machine, I'd question the sanity of whatever person put it there.