Demagnetized Pick Up after Guitar Repair?

[Helmholtz]

thank you, I'm looking at AMAZON but they are a mess... nice place to find fridge magnets though

Mine are actually fridge or board magnets similar to these: https://www.amazon.com/LTKJ-100PCS-M...3551960&sr=8-2

i am assuming the magnets diameter must match (approx.) the pole's diameter, with is 5 mm in my case

I prefer 8mm magnets for 5mm poles. Always give perfect results. No experience with other neo sizes and numbers.
From magnet theory I expect smaller diameter neos and less neos to produce a less focussed/less uniform axial field that may not penetrate the alnicos deeply enough.

how to be sure I am polarizing the Pickup in the right way (north or south).

Principle is: like poles repel and demagnetize, unlike poles attract and magnetize.
You may use a compass to identify poles. Or get one of these:https://www.amazon.com/SEOH-Magnetic...s%2C258&sr=8-5

Might be a good idea to practice with a scrap (strat) PU.
If your bridge PU is good, leave it alone and never let the neos get close, not even for the fraction of a second.

[TelRay]

Mine are actually fridge or board magnets similar to these: https://www.amazon.com/LTKJ-100PCS-M...3551960&sr=8-2

Principle is: like poles repel and demagnetize, unlike poles attract and magnetize.
You may use a compass to identify poles. Or get one of these:https://www.amazon.com/SEOH-Magnetic...s%2C258&sr=8-5

Might be a good idea to practice with a scrap (strat) PU.
If your bridge PU is good, leave it alone and never let the neos get close, not even for the fraction of a second.

thank you, sir!
yepp... those magnets you show kept popping up on my screen but the word "fridge" threw me off every time... i was looking for "more refined" terms like rare earths or neodymium
thx!
good tip on identyfing polarities!
no scrap PUs at the moment... well, until i try to fix this one that is and depending on how it goes
i am waiting for the repair guy to conclude if he accepts responsibility or not. he told me yesterday a new guy was doing part of the job on my guitar and he needs to ask him.

To anyone who is recharging the magnets ,Most JM pickups are rw/rp so you need to charge them accordingly

thank you for jumping in and highlighting that point, that's exactly what i meant in the post just before yours "I've read on the SEYMOUR DUNCAN specs (vintage jazzmaster neck) that this one has a reverse polarity winding (RWRP)"

can you be more explicit (for a person like me who has never layed a finger on a pickup before) about what do you mean by "charge them accordingly"?

thanks again!

[Helmholtz]

no scrap PUs at the moment... well, until i try to fix this one that is and depending on how it goes

No real risk to permanently damage a PU with the neos. If you accidentally demagnetized a pole, just remagnetize it. The method even allows to flip PU pole polarity.

[TelRay]

thx!

any comments on copperheadroads' warning? "TMost JM pickups are rw/rp so you need to charge them accordingly"

[Helmholtz]

thx!

any comments on copperheadroads' warning? "TMost JM pickups are rw/rp so you need to charge them accordingly"

I think he just meant: Don't change original pole polarity.
You can use the compass to verify if neck and bridge PUs have opposite magnetic polarity, which means rw/rp PUs.

[TelRay]

thanks!
now it's a matter of waiting a couple of days and see if this gentleman is going to take responsibility for demagnetizing the PU or not
Plan B is clear now thanks to y'all

[TelRay]

time for an update.
I've got my guitar back a couple of weeks ago. the tech purchased a new pickup (Seymour Duncan Vintage Jazzmaster) and replaced it at no charge.
Everything is working well.
He gave me back the old pickup too so I might at some point restore it, but right now I don't have any other guitars that will fit this PU.
Thank you guys!