Fixing vintage dustbusters
These aren't that hard to fix. The problem is almost always leaking/dead cells. Pull the unit apart, see how the batteries are configured, buy 'sub C ni-cad' rechargeable batteries to replace them.
They are 1.2 volts each. The most I've seen starting with model 9333 is 5 batteries. Soldering and arranging pacs in order required. After the max ni-cad rating of 6.0 volts, they launched into lithium.....but a completely different dustbuster.
The new batteries are better than the old ones. More mAh than the originals. I should start a service.....lol. My favorite is the 9338 which has contacts in the nose to match the detachable upholstery/rug cleaner unit with its own motor.
The prices on eBay for bad battery Dustbusters are more than insane. I can't believe anyone is paying that for them.
Dudtbusters don't really work well until you get to 6 volts and at that, they're best at kitchen cleanups(dry), or some crumbs or debris on a hard floor.
I'm always looking for repair units!
Kevin