Point motors - Bodge of the month, or
 

"This defies the laws of physics". :eek: Cue spooky music......

The layout that I made is about 5 years old and has been stored unused in the garage for the last four and a half years. It has 8 motorised points (Gaugemaster "Seep") driven by a capacitor discharge unit. They all worked superbly 5 years ago.

But when I tried it again recently the points were useless, only feebly moving the switch blades over half way at best. I WD40'd the motor pistons, and even replaced the CDU, with no improvement at all. The input voltage from a new controller at 18v was better than the 16v I used before.

However, in the grand engineering tradition of aimlessly prodding things with a screwdriver, I discovered by accident over a couple days messing around that by just lightly touching the blade of the screwdriver on the side of the piston made the motors work perfectly again.

So I have hung split-washers on the middle of the piston(s) and they all work perfectly. Two brand new motors work perfectly without the bodge washer.

Now, I am gald to have avoided the hassle of unsoldering everything to replace all the motors, but I just cannot understand why this worked. The problem is weird, and the solution impossible, even with my doing A-level Physics, and an degree in Engineering, once upon a time.

I know Gremlins really do exist of course.....;)

It looks like the core of the point solenoid has suffered a thermo-magnetic transference. This is most likely due to the capacitor discharge unit being left in a charged state when the layout was last used (5 years ago) and the layout having been stored in a room where the temperature has regularly cycled.
The screwdriver blade and the split-washers are acting as sacrificial balancing components which restore the non-magnetic equilibrium of the solenoid core thus making it operable again.
If it isn't that....I don't know what it is.

:) Wow ! Thanks! - I just knew it was something like that all along.

Looks like "sacrificial balancing components" is going to be my new Google "search phrase of the week".

Joking aside. It's weird, isn't it?
It will be interesting to see if the motors carry on working or if you are able to remove the washers at a later date.