Fuckit - Robovac died ...

Why not...

I would assume, in modern life, a thing like this would have plastic gears and the noise came from a gear tooth failure. Brushed motors, can have a brush failure. Good designs, the brush cartridge can be removed and a new brush fitted. But again, modern life, nobody stocks the brushes (carbon rods maybe) for replacement. There is a braided copper electrical connection on the end of some brush designs and when buying a brush, you also ask the supplier for the "crimp" that goes with it. As the connection is crimped for security. You don't solder those on as the solder might melt and if the solder flows down the copper wick it ruins the suspension principle achieved by the copper wick in the first place. The copper wick is intended to make a flexible electrical connection that can carry considerable amperes.

While the noise might be the motor, it is more likely to be something in the drive train which has failed. A cheap element designed to fail, versus the way we used to design gear trains. The gears may be exposed to the airflow, grit could get into the gears.

They can make gears out of something that has unbelievable hardness. I've seen gears, the teeth edges are just as sharp as the day they left the factory. These are gears not made out of mild steel, whatever they're made from. But things like laser printers, the gear trains in those can be plastic, and eventually something no longer meshes properly and the drive train fails. Why exactly would a company use a good quality drive train, when plastic is so "cheerful".

Paul

Well it was whizzing along nicely until something (maybe a tangle) caused the main brush to make a horrible noise. So I am 100% certain that is (currently) the only fauly.

The unit is sealed and the gears are clealy somehow ****ed.

However even if I just forked out £8 for the motor unit, the thing as a whole is so fiddly that putting it back together functionally feels like a challege too far. Especially as my close work eyes are done for (glaucoma - especially bad in one eye).

And the how much to try and get for it - especially as from experience trying to sell *anything* brings in the total chancers who will say "it doesn't work" etc. Which is more hassle than it's worth.

Which is why people sell perfectly good kit for 'spares or repair'.

I have a 1940s portable valve radio here in really good condition and in perfect working order as far as I know - its owner stopped using it when someone gave them a transistor radio.

But if I do list it, it will be under 'spares or repair' because I cannot test it.

Well the dissembled unit is in a box.

I've never really been an eBay fanatic. However in my last role I had to spec a roomful of kit the CEO wanted to put on eBay, so I've seen it done.

I bought a 'faulty' robovac for cheap. Turned out the main motor had bad bearings, so replaced for a few quid from Aliexpress. I also killed the charger along the way (oops) so had to buy another of those. I had to buy the accessories for it from Aliexpress too, but they were cheap also. Eventually deemed to be too loud to use, I sold it for about £200.

There are some good microscopes now for close work, either cheap USBs or standalone ones with screens.

Theo

I realised I was hitting limits when trying to prise a connector out two wires got pulled out of the block. I was *just* able to put them back with a phone magnifier and a holder.

I might list the whole box - with charger - for £30. Not sure yet.

I have one of those helmet swing down magnifiers, plus a set of tweezers which helps a lot. Fortunately hands not shaky yet.

Hmm, depending on what model it is, bits it has with it etc I might tentatively be interested. I've sent you a mail, but not sure if you read that mailbox / it got stuck in a spam trap / etc. The email on this post works...

Theo

Replied :)