Wurlitzer 3210

Hi everyone, I picked up a Wurlitzer 3210 a couple weeks back and have been cleaning it up and trying to make it work. The biggest issue I have with it is when I make a selection the carousel does not move to the selection until I hold in the cancel button on the back of the amp. If I hold cancel button in it will load the record play then if I hold it again it will then unload and move to the next selection. I have taken the amp and the record changer box out and checked all the solder joints and tested all the caps. I took the relays out and tested them with a 24v power supply and they function fine. The manual says something about the Service Switch I found in the wirering diagram (posted below) but can’t find it on the machine any ideas where it is? Also I’m getting a loud hum with it just setting there I thought maybe it was the amp but again all the caps check out good. I powered off the unit unplugged the phono inputs powered it back up and no hum. Maybe something in the wiring between the amp and the cartridge?

Quick answer, as I'm short time--
Check NC contacts on end of record switch and in amp.
Service switch is a little black "sliding switch" located on junction box
Ron Rich

Ok bear with me lol still a bit new to these things and well this is the first record player I have ever owned or used. Is the junction box what I’m pointing to in the picture below? Really don’t remember seeing any switches on it or in it but will take it out again to double check. NC is that a normally closed contact? End of record switch would that be up by the arm?

Yep-Yep-Yep--you got it ! Ron Rich