broken bits: Bosch GWS 9-125 S grinder

Tear down and reassembly of our Bosch GWS 9-125 S variable speed grinder to learn the source of the terrible noise and heat that it is producing when it is turned on. Inspection of the possible consumable parts to replace...
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[@ianc4901]

That sound is because both sections of the coil are energised at the same time and it is trying to turn in both directions at once.
Normally there would be a capacitor to prevent this and it has probably failed, it will be a small black rectangle approximately 14mm by 10mm (possibly a little smaller) and connected across the mains wires either at the switch or the motor, this will need replacing.

[@sailorama]

Thank you for the technical detail - will look up the part to see how possible it is to acquire here. I suspect that something failed! 👍

[@steamlilly]

those graphite rectangles are called rotor Brushes.

[@murrat]

I'm amazed at how you took that apart and reassembled it so quickly.

[@sailorama]

Through the magic of editing you all don't have to sit through my humming and hawing and pauses 😆

[@SoItGoesCAL34]

I'm confident you will find a way as y'all are very resourceful :)

[@sailorama]

Thanks for believing ☺️

[@saylaveenadmearedead]

You are so dang handy... I can see you, Robbi and the 12 kids on a deserted island living a fine life!!!

[@sailorama]

Haha - with all 12 kids and lots of broken tools furiously, unsuccessfully trying to fix all the broken shite on the island 😂

[@linaldosoares3290]

Esse vídeo foi uma aula para mim conseguir ajeitar a minha esmiladeira.

[@nubaratin]

a Bosch deixou a desejar na refrigeração dessas máquinas e são vários modelos diferentes ..esquentam demais em uso mais prolongado por falta de 1 hélice pra resfriar bobina e induzido ao acontece isso aí direto nelas ... o uso delas é no máximo 5 minutos e tem que deixar esfriar

[@brockallentaylor]

I would suggest cleaning out the gaps in the commutator. Some are probably bridged and it causing multiple windings to be excited at the same time.

[@sailorama]

Good tip! thanks - maybe something I can do here on the boat

[@russellsmith8609]

You could try cleaning the armature, that area where the brushes contact, with brake cleaner and a brush.

[@sailorama]

Thanks! Perhaps cleaner might help. I tried brushing it clean only, and found another channel that described testing it with a multimeter...that's where I hit a wall because our multimeter is also broken 😂

[@corcel1977]

Induzido em curto

[@AndersonDaSilvaAureliano-ve8yf]

Esse é o problema?

[@TheGolopablo]

Hi Justine
What about the red speed selector at the bottom...maybe dust accumulated between carbons...it is a reostat...give it also a clean with some contact cleaner spray
Pat Choco for me 😃

[@sailorama]

Thanks for the tip!

[@steamlilly]

Clean the rotor slots from any debris. brushes leave some, there can be dust and such. then check brush springs. do they push brushes hard enough? if not, brushes will jump on vibrations and allow sparks and arches, grinder will get hot. if arch is long enough it can jump to opposite brush, making grinder to jerk time to time. if brushes press good, no arch.

[@sailorama]

Your explanation makes a lot of sense, unfortunately I don't think that there is any problem with the brushes - they seem to spring into place nicely, snug and secure, touching the armature. I'm thinking there is something wrong with the armature.

[@phillipobrien7365]

I had the green Bosch grinder (handyman rather than tradesman quality) and it went through contact brushes in no time. Changed them twice and no improvement, so junked it and bought a cheap Ozito which is still going well. Bosch used to be really good quality, not so much now.

[@sailorama]

The brushes seem to be okay - what did your brushes look like when they stopped working?

[@phillipobrien7365]

@@sailorama Worn right out, happened with new grinder, then 2 new sets wore out after very short time.

[@TheGolopablo]

Y si no puede ser un condensador...que no sé si en ese modelo se puede cambiar o va integrado en la placa
En motores eléctricos en general, si falla el condensador, hace un fallo parecido
Igual te toca cambiar toda la placa

[@sailorama]

Gracias! Pienso que eso es posible. 👍

[@tamatadesignexeter]

🤣 sorry but that just made me laugh. Great vids my friends.

[@sailorama]

Glad you enjoyed it 😝

[@adayinthelife5496]

Are they supposed to sound like a coffee grinder?

[@ianc4901]

They always sound like coffee grinders because of loose tolerances

[@sailorama]

Yeah - but a little stronger sounding, and should produce less heat 🫤

[@anjanasadaruvan5306]

I am use bosch gws 9-115 s 8month
no poblom User damej

[@ottonormal5833]

Hi
Iam not very well versed in this. The stalling seems to indicate a mechanical fault or a to weak magnetical field, to me. But I have no expertiese in repairing these tools.
I hope someone else has a more helpfull answer. Maybe look at some repair videos on youtube. I enjoy the "post apocalytic inventor" channel with his repair of tools found in the junk yard.
Good luck you two

[@sailorama]

Haha - I answered similarly to another comment - I found another channel that described testing the armature with a multimeter...that's where I hit a wall because our multimeter is also broken 😂

[@sergioivanmartinezlaura]

Jajajaj🤣🤣🤣🤣 y que paso jajaj

[@sailorama]

🤣