Hellzero

And here are the 4 lugs explained, but I doubt your two "techs" can understand this very simple "diagram".

The battery is always on. Your two techs are utter idiots who can't even use a simple multimeter. The non soldered lug should be the battery negative, because where it's soldered is the permanent ground, like where the ground is soldered, so a battery always on. As I wrote, there are different barrel jacks, and this one is a 3 lugs plus ground.

An inventor is someone who, of course, invents things, but is also someone who imagines something new ("he designed a specific electric bass for easy mass production"). The second part is what Leo Fender did all his life, while listening to musicians demands, hence, for example, the Stingray and his active circuitry.

And I'm the pope.

You nailed it.

You forgot to include the price of the case that is not included and mandatory for shipping... Now time to get a second job!

Leo Fender was NOT an engineer at all, but an accountant and was a radio repairer hobbyist, nothing more... But sure he was an inventor

Erm, erm, the he is a she. And she's named Ivca. 😉

And the master Martin Luthier King.

Okay, here it is explained differently: If you leave your jack always plugged, a modern circuitry preamp will take approximately 2 weeks to completely drain the battery. But an old chipset from the 70's named LM4250 and used in the Stingray 2 EQ preamp will take 4 or 5 years to completely drain an always on battery, but that chipset is the exception confirming rule.

Welcome to the club, when I started piano, I was sometimes playing 8 hours a day, which resulted in a superb tendonitis on the right arm forcing me to stop playing during 6 months... Well done.

Yep, and there are quite a lot, but having owned luthier basses almost from the day one didn't help with what I may call mass produced "basses".

A gentlelar...

My 1979 pre-Ernie Ball has been refinished the same natural finish as it was originally, but I don't care as it sounds amazing. That said, the OP's Stringray is a 1989 model, not a 1992 model, which the year he bought it, so a tad bit more on the vintage side.

PS: 15 days is the average time a battery will take to be dead flat with a modern chip even if the 70's LM4250 chipset will take something like 4 or 5 years to totally drain a 9 Volts battery when always powered...

Can you put a photo of the output jack with the wires connected, which let us see where these wires are coming for?

Sorry, couldn't resist after seeing @ziggydolphinboy collection...

This is where Jaco is at his best, listening to the others and playing music. Well maybe his solo part is not mandatory here, but as Joni Mitchell said, it was the price to pay. The two studio albums are excellent too: Hejira and Don Juan's Reckless Daughter. You can also try listening to Bright Size Life, with Pat Metheny too, where Jaco was not on the booze and dope at all.

To be very clear: somebody assembling parts IS NOT a luthier, he has to craft them, neither is the guy only changing strings and tuning (when he can) an instrument. There are so many people pretending to be luthiers and who are just wallet emptiers.