Affiliated boaty electrical problem.

[KREW2]

I have a Dodo juice rotary polisher with a digital speed control which has failed a few times. The latest one failed last year I took it out cleaned it with a brush and a drop of meths and it ha been working fine until yesterday. Pressed the start and zilch, nothing, nada dead as a Dodo.
I removed the speed control, cleaned and replaced, all works fine but only upside down. I have checked for a loose wire but nothing was evident. Should move to Aussie

 

[jamie N]

At a guess I'd say that it was a loose wiper on the speed control pot.

 

[Minerva]

a-ha! Stick a harken sticker on it and market it to someone who dry sails a racing keelboat as a super dooper go faster bottom of the hull polisher BUT they will need to buy the corresponding Harken keel polisher to compliment it.

 

[KREW2]

Anyone any idea why this is possible.

At a guess I'd say that it was a loose wiper on the speed control pot.

Thank you, what is a wiper. If I have a loose one I 'll tighten it.

 

[mjcoon]

Anyone any idea why this is possible.

Thank you, what is a wiper. If I have a loose one I 'll tighten it.

wikipedia.org/Potentiometer
"Pot" is short for potentiometer. "Wiper" is the moving contact that moves along a resistive track within the unit. Typically they are used as volume controls in classic audio equipment. As the track or wiper gets dirty the control makes noise when moved. When instead used for related purposes such as speed controls a faulty pot makes the control unreliable. Sometimes they improve by being worked backwards and forwards over their full range while powered off. If dismantled then switch cleaner might be squirted inside.
Of course a "digital" control may not have a pot.

 

[KREW2]

The speed control is digital, 1000rpm to 3000rpm. My Spin Doctor polisher is on it's third control, so rubbish really. with the pad facing down nothing turn it over 108 degrees and it works fine through all the speed range Laying my boat on it's side is not an option.

 

[mjcoon]

The speed control is digital, 1000rpm to 3000rpm. My Spin Doctor polisher is on it's third control, so rubbish really. with the pad facing down nothing turn it over 108 degrees and it works fine through all the speed range Laying my boat on it's side is not an option.

Sorry, but what does "digital" mean? Do you enter speed using a numeric number-pad? That would be digital in my world, but with no pot. Or turning a knob (perhaps a pot) which registers just a few chosen possible values on a display? Or using just two buttons, up & down, which also choose values on a display (with no pot involved!).
I get the problem with gravity and orientation but not what component might be gravity sensitive. You said you solved the problem before, yet don't know...

 

[KREW2]

Thanks for your help. There is an on and off switch then you press the + button to start it at 1000rpm then increments of 1 push increase rev s to 3000rpm the minus button obviously reduces it back down, your up and down button description is the one.

 

[KREW2]

Thanks for your help. There is an on and off switch then you press the + button to start it at 1000rpm then increments of 1 push increase rev s to 3000rpm the minus button obviously reduces it back down, your up and down button description is the one.

Can wind this up now. Took out the armature out and only one of the brushes popped down. Took them both out plenty of meat still on them, gave alight brushing and put on a bit of gun oil. reassembled and all is fine. Both springs were good, so still baffled as to why it ran fine upside down.