Because the service technician did not have the correct part with him when he went to the service call on location. Goal is to get the machine up and running getting it making money. If the improvised repair works, it stays.

Looks like this one may have lasted 45 years or more.

Ding! Ding! Ding! Winner winner - chicken dinner!

I'm sure most of my games have springs that are not the specified spring. They work just fine.

In the universe of hacks this is at the bottom of the list. Are you really going to shut a working game down while you order one spring?

Plus back in the day there was little if not 0 market for a collector of pinball machines and these games were destined for the junk yard as they would be replaced in a matter of a few years. From one perspective all these EMs are just gravy over profits from the operator.

What they said above. I got my Beatles on a Saturday evening around this time last year. Just a few games in, the upper left flipper was returning to rest very slowly, sometimes not at all. It's 9pm, only option was Home Depot, a pack of various springs for about a dollar 79, tried to match it up as close as possible and had to cut a few loops off of it, still working great a year and several hundred games later.

Ha ha. I did the same thing to a spring on my Flip a Card Ball Count Unit and felt a little guilty until now.

There can be times when the right spring matters. I had drop targets on my Old Chicago that would not stay up on reset. Sometimes they did, sometimes they didn't. There is some slop in the mechanism but the first step and the easiest is new springs. I got the correct spring from PBR since I had to place an order anyway and that cured it.

On steppers, though, you can usually find one that will work just fine. I've got a box full of springs and when I suspect one on a game is an issue I root through and find one close enough that works and leave it at that.