I will attempt to answer some of his questions...>>>
no candle and the call light button does not light when pushed..
If you can...use a multimeter and check the 2 candle lamps for continuity to make sure they are okay.
The "call button" lamp will not light on an S+ unless you rig it to.
.. no led light on coin comparitor ....
This CC LED lamp ( sometimes they're green as well...color doesn't matter...) only comes on
when the machine door is closed and the door optics are fully functioning.
...no led display at all, the only light I do have is the denomination light...
There are two black Molex connectors that attach from the door harness into the reel glass display panel.
I'm doing this by memory...>>> the Molex with the blue wires plug into the display near the CC ( used primarily for the Denom lamp.) while the other Molex plugs into the display nearest the door hinge.
There is yet another small Molex on the door harness near the door hinge but that one is generally
for multiple line games to light up 3 or 5 coin light shadow boxes.
You see this shadow boxes especially for 5 coin bet game reel glasses on the left-hand side -
each shadow box lights up depending on how many credits you'd bet.
Normally this Molex is tucked into the harness and is kind of short and is usually a 6-pin Molex.
The Molex you plugged into the reel glass display...how many pins does it have?
It would be used for the power for the "windows" on the reel glass display.
If anyone is near an S+ - please correct me in the two reel glass Molexes please?
Especially on how many pins each Molex should have?
Thanks...I'm nowhere near an S+ at this time to verify.
I strongly agree with Poppo in that you should check the motherboard's traces and loose coins.
This is the circuit board that is on the floor of your machine.
It is used primarily for routing power and signals in and out of your machine.
The MPU (The circuit board that has the battery and big black knob) is the main circuit board that houses the game and reel chips.
If you have more questions...please feel free to post anything that you might have
and we will try our best to help you out.
We really want to help you get your machine up and running the way you want it!!!

Last thing...I can see in your photos of your motherboard power Molex (the white one that goes to the motherboard from the power supply) that you've been squeezing and pulling it up by grasping the white wires only.
This is an extremely bad habit.
You should always try to grasp the Molex housing - rather than the wires.
It's very easy to ruin the female receptor pins that way.
Plus...you can easily very slightly pull out one the wires slightly out just enough to cause an intermittently working ground.
It is now essential that you turn off the power switch and firmly push each on of those wires back fully into that white Molex housing to rule out any possibility of the problem being with that power connection points.
They are critical to the proper functioning of ALL of the components in your machine.