Have had a cheep demagniser blue one from China after cleaning and oiling movement was running well nice motion wanted to demagnetize it before timing after demagnitizing lost balance Amplitude removed balance found balance cock end staff was mushroomed putting this down to holding movement to close to demagnetize the old style demagnetize usually surrounded the movement distributing the field evenly so what I am saying be careful not to hold the movement to close to the demagnetize most of you probably are aware of this issue but maybe some are not cheers

The demagnetizer is it a single pulse type or a button you hold and has a constant cycle.
how did you demagnetize the watch?
photo of tool may help.

Hi Chris is a blue device with a red momentary on button about the size of a small packet of smokes heaps of these Chinese units available
Held movement on top of device with power on for about 2 seconds and then pulled movement away before turning off
When movement was held near device could actually feel movement vibrating strongly

Device in question

Hi Jeff,
I would be a bit suspicious of that device it look like a "demagnetize anything device" of unknown power output, if I remember you are on 230vac also? and I bet it doesn't have a voltage changeover switch so you therefore have a lot more energy than if used in USA etc.
I would look out for a traditional oval style watch demagnetizer rated for 230v ac and you can eliminate any concerns, I have used these for many years without problem.

Also it best to hold the watch well clear of unit press and hold the button take the watch to unit gently move watch around in field then remove arms length away before releasing the button.

IF you put the watch on the device and switch on, there is a large initial surge and pulse.
hope that helps

Yeh thanks Chris I think you have hit the problem I have looked at advertisement for these and I didn't realise the same unit does 240v and 110v without any changeover switch so the degauss field will be many times stronger explaining why it is mushrooming the balance pivot probably not a problem on 110v thanks mate