Hi jefwv
in this post I write some theory (only). About "looking for the fault": See my next post (to come).
Look at my BMP. On top from right to left You see a thick line / a thick wire. On the left it is marked "RED". Follow "RED" to the right -> through a Normally-closed switch on Reset-Relay" -> through the part "Closed-Switch on Game-Over-Relay"*** -> and from now-on the color of the wire is "BLACK"-> to the right -> not on my BMP -> Fuse -> transformer (power-side).
On the bottom of my BMP from right to left You see a thick line / a thick wire YELLOW -> to the left -> not on my BMP -> transformer (returning lug). (You may also look -> schema -> Page-3 and then page-2).
"Closed-Switch on Game-Over-Relay"***: Sometimes in a schema they draw (show) only half of a M&B-Make-and-Brake-Switch. They give a "hint": Actually it is a M&B-Switch BUT HERE we focus on the part "Brake". The wiring of the part "Make" of that M&B-Switch is drawn somewhere else in the schema (we make two drawings for better understanding).
OK, on top of my BMP there is "Power"-Wire (color RED or color BLACK). On the bottom there is the returning (to transformer) wire (color YELLOW).
Between "Power-Wire" and "Returning-Wire" there are hooked-in many Coils (of Relays) - these coils are mounted "parallel".
Example "Coil of 100-Point-Relay": (transformer -> Power-Wire -> through the coil -> wire -> switch -> wire -> switch -> wire -> Returning-Wire (-> tranformer). These switches are mounted "In series".
When the switches are all closed we have a circuitry and electricity can flow and therefore the coil produces magnetism "for the relay to pull". (As a side-effect the coil produces some heat).
If we open one of the switches: Current can no longer flow -> the relay gets inactive.
"A good coil <-> a damaged / ruined / shot / dead coil / blowing-a-fuse-coil":
Instead of "Your measured 17.6 Ohm" I write here "20 Ohm" (it suits me better).
Lets assume "on the coil is wire wound of "lenght 100 yards"". These 100 yards have an insulation around - no plastic, no fabric - just coating / paint / lacquer. BUT with this lacquer the windings are insulated apart. We do measure 20 Ohms on the coil. We would also measure 20 Ohms if we would unwind the coil and measure the length of these 100 yard (straightend from Start-Point to End-Point).
AAA: Our 100 yard of such wire (straightend) we will measure 20 Ohms.
BBB: If we take only 50 yard of such wire (straightend) we will measure 10 Ohms.
CCC: If we take only 25 yard of such wire (straightend) we will measure 5 Ohms.
DDD: If we take only 10 yard of such wire (straightend) we will measure 2 Ohms.
EEE: If we take only 5 yard of such wire (straightend) we will measure 1 Ohm.
A "rule of electicity" is: "Volts = Ohms times Amperes". The pin has about 25 Volt, so
AAA - 1.25 Ampere
BBB - 2.50 Ampere
CCC - 5.00 Ampere
DDD - 12.5 Ampere
EEE - 25.0 Ampere
On the 100-Point-Relay-Coil you measured "2.2" Ohm -> 25 / 2.2 = 11.363636 Ampere.
In the schema "Wms Hot Line" I see "24 Volt and a fuse of 15 Ampere. 24 / 2.2 = 10.9 Ampere. Your fuse does not blow.
If we take EEE (5 yard, 1 Ohm) -> 24 Volt / 1 Ohm = 24 Ampere. The fuse WILL BLOW.
Another "rule of electricity" is: A side effect of current flowing is "Heat". The more Amperes - the more heat.
When a coil gets hot and hotter ... the insulation / lacquer starts to melt or to change into coal (think of charcoal) - well, whatever - a local short is made -> the electrons take the shortcut. Other local shorts are made (other shortcuts) -> -> -> Our "100 yards of wire" -> 99 -> 98 -> 80 -> 70 -> ... AND THE SHORTER THE WIRE, THE MORE AMPERES FLOW AND THE MORE HEAT AND THE MORE MELTING OF INSULATION AND MORE SHORTS -> -> THE COIL WILL BE BURNT / SHOT AND PRODUCES A real SHORT -> THE FUSE BLOW.
jefwv, You should replace the coil of your 100-Point-RELAY - soon Your 15-Amp-Fuse will blow (You then say: I have a short in my pin). In the schema I read "M 29-1100" - a very common coil (easy to get). Greetings Rolf