The voltage remains whether or not the power switch is on.
I have a feeling you have something wired wrong. If the power switch is OFF, you should not have any voltage. PERIOD.
Please review your wiring as per the Assembly guide and the diagram above.
I'm wondering if I wired the transformer wrong because on the transformer it says that the red and yellow wires carry 18V and black and orange carry 0V, but your diagram above says differently.
There is no need to "wonder."
Please follow the assembly guide.
Do not assume anything.
The diagram above works and the assembly guide is correct.
There is no need to "wonder." As I said in my instructions....
connect RED and ORANGE wires together, connect to "CT" pad of PSU
connect BLACK to "AC1" pad of PSU
connect YELLOW to "AC2" pad of PSU
Or maybe my assumption that AC1 and AC2 on the PSU are where the 18V wires go is wrong. At any rate, I tried it both ways and got the same result both times. Any ideas on what the problem is?
There is no need for you to ASSUME anything.
DO NOT ASSUME ANYTHING.
Everything is spelled out in the assembly guide and the pictorial wiring guide above on how to do it.
JUST FOLLOW THE INSTRUCTIONS.
Do not experiment and try different ways.
There is no need for you to "try both ways" or try different things. There is a correct way to wire this and all you need to do is follow it.