Hello everyone.
First, I would like to say hello to everyone from Pinside forum because it's a great place to learn pinball technical information. It's also my first post here, so please forgive me maybe naive questions. So far I have focused more on arcade games (yeah - Williams Defender finally at home), but I have got also one - Shangri La pinball and I am dreaming to bring it back to be playable. Especially because I love graphics of this EM.
Few information about my pinball:
- it was bought as not working, unfortunately without backbox.
- it was quite dirty inside, but after cleaning many switches and some checks inside it was OK for many days - it was possible to 'insert coin', operate with flippers and all bumpers worked fine. Only some bulbs replaced.

Right now, after few months of 'vacation' of Shangri La in the basement and start test it burned 10A fuse for 24V.
Now I understand, that the first approach was not good - to simply clean and try to start without deeper analysis of this pinball logic.

I am looking for any information about start sequence of this particular Williams EM.
I was tried to follow it using schematic from IPDB, but still there are some points I am not sure about

Before fuse burned I have started it:
Plug AC then =>left flipper switch initialized Lock Relay=>6V lights ON => Insert coin/s => ball kicked and ready to play.
I am looking now for start sequence with more details about (expected) coils/switches/relays behavior.

Of course no backbox limits not only full fun of playing, but also makes difficult to see more feedback during start/play sequence when investigated. There is no score, no player/ball # details and finally no sound.

After changing 10A fuse I have tried to start it again.But without success:
power ON=>push left filpper switch => lights ON => push 25c insert coin => Coin Relay and Reset Relay and 25C relay are activated (I have used slow motion camera to catch it ) => then nothing happens.
After that - ball is not kicked to start a game, flippers do not work, manually triggering bumper's playfield switches do not start bumper's coils.
I have also checked Tilt switches inside the box to be sure that are not connected (ball tilt switch) or disconnected (kickoff, door switches).

additional questions:
1) It's possible to play and debug it without backbox ? (yes I was able to 'play' before, but not sure about all additional switches position now. I am pretty sure motor switch should be off)
2) What about high tap connection. When I bought the pin it was connected to high tap. I have also noticed few days ago that the main AC was wrong (220V instead of 230V that is here in Poland for many years). So I solder the transformer to use actual 230V and with normal 24V instead of High). There is 24-26V there now so I suppose it's not the starting issue root cause.
3) It's normal that I have 110V on insert coin leafs?
4) What is the role of the button on the front of the pin? It is not 'free play' button ? (no reaction when I use it). I cannot find it on the pin schematic.
5) Can you confirm that backbox is needed for it even if big bell and kick coils are in the main box of the pinball I have? Maybe some workaround connections to get the sound without backbox?

I know, that the logic of every EM pinball is complex, but I hope that someone will be able to help me start fixing this great pinball.