Spring missing on 1974 Daiichi machine

[645development]

20221009_193005.jpg
Got a hold of a pretty decent 1974 Daiichi. There were a number of things going on (like the jackpot intakes being jammed with balls), but pretty much everything was easy to resolve if you knew what was going on. The only thing remaining is to hook up a power adapter to it (gotta do a bit more research on what goes to each of the 3 screw in terminals), and the ball launcher spring is missing.

Does anyone know where I can get a replacement, or does anyone know the measurements and tension of it? I'm wondering if I can find something that would be fitting that could work as a replacement, but I have no idea what the tension/resistance should be!

[sparky kilowatt]

I checked one of my vintage machines, pretty sure they're all the same size, about 5.75 inches including the rings on either end of the spring. The spring tension is adjusted by moving the right side mounting tab of the spring on a little finishing nail.

[InsaneDavid]

You can find a suitable replacement at most hardware stores over with their general fasteners. Sometimes they're kept in the odds and ends or specialty drawers. Find one that's long enough and then just cut it to size. Also good for anyone who has an overly rusty spring on a vintage machine.

[Bowl987]

Don't forget to put a "prize" inside your new spring.

[sparky kilowatt]

Don't forget to put a "prize" inside your new spring.

Not to hijack this thread, but why is it they have old newspaper rolled up inside of them?

[takethecastle57]

Prevent rust ?

[Moparformances]

Not to hijack this thread, but why is it they have old newspaper rolled up inside of them?

sound deadener

[SibSr]

A couple months ago I went looking for these springs. I found my central Florida Home Depot and Lowes both had the same small selection of springs with nothing useful on the wall.
Ace Hardware had a multi-compartment box that held promise, but was not fully stocked and again nothing useful.

Moved to the internet and learned that I was looking for an "Extension Spring" with "Double Looped ends". Ended up on Grainger.com, and found the closest thing I had seen to what I was looking for.

grainger.jpg

Grainger part #782EZ4

Is the right type of spring, with the correct length and diameter, and only a small fractional difference in the wire diameter.

6" or 150mm long
Diameter is 9mm
Wire size is slightly larger at .047 instead of the 0.35 I measured on my sample spring.
"Music Wire" construction means oiled steel rather than stainless steel.

I'm picking up two of them at Grainger tomorrow and will report back on their suitability

[mxfaiman]

sound deadener

Yep this is the exact reason for the newspaper. As well as reducing vibration when the spring is released.

[SibSr]

The spring I found is too strong.
The Grainger springs are the right length and diameter, but the slight difference in wire diameter might be ok on a shorter spring, but it adds up to a lot of extra resistance spread over 100 coils.

The search continues...