I have been using a SSR tester that Roger (51Ford2) designed and it has served me well. I strongly suggest that anyone how runs a display with external SSRs to have an SSR tester to help trouble shoot any problems they might have with their controller SSRs and related cables.
While maintaining my display this past season I found that I was in need of a SSR tester that did not require holding a momentary contact switch to keep a certain channel on. I have several light strings that are connected directly to my SSRs so if a light string burned out and I needed to test it with my Light keeper pro. I had to find a helper to hold the tact switch on so the lights would stay on. So I came up with this SSR tester as a solution.
This hands free tester has the momentary switches and a DIP switch that you can turn on any of the four channels and leave it on to make it easier to troubleshoot your light strings. It is the same circuit that Roger designed except that I added the DIP switch in parallel with the tact switches so you can use either set of switches to make things easier for what you are doing at the time. I also added a GND to pin 7 of the RJ45 connector this was added to make the power LED on your SSR light up when it is plugged in to the tester.
I have attached the required files in Eagle format for home etching. As with all of the things I design, anyone who wishes is welcome to use these files as they are or further modify them to fit your needs