braun multipractic handblender model No 4-166

[willie.williams]

hi all i'm new to this thread and new to electronics i need expertr help in trying to fix this hand blender , i have tried by replacing the potentiometer (250k) but no difference the speed still does not alter when you adjust the potentiometer wheel it looks a simple cct but when your not a expert in this area it looks a mine field
can anyone help ??? iv'e inserted a photo of the offending beast and would be greatful for any advice
kind regards paul

 

[tunedwolf]

If it is running at full speed constantly, the most likely cause will be the TP216 triac, if it is short circuit MT1-MT2 then replace the diac that goes with it.
Obviously check that the little preset is not open circuit too as this sets the min speed along with the transistor and resistors, particularly the 330K and 100K ones.

rgds

 

[willie.williams]

hi, thanks for your reply, the blender does run constantly at top spped, i'm assuming that the diac is the component that is just in front of the triac in my picture ( black with silver stripe value/marking 1N 4004)??
i have tried to source these on the web, rs components site is very confusing to the un-initiated, can you suggest some where i can purchase these two components from and how to find them.
thanks Paul

 

[ben7]

If it is running at full speed constantly, the most likely cause will be the TP216 triac, if it is short circuit MT1-MT2 then replace the diac that goes with it.
Obviously check that the little preset is not open circuit too as this sets the min speed along with the transistor and resistors, particularly the 330K and 100K ones.

rgds

Did you think that the diode in the pic was a diac? :S
It only has one band its marked 1N4004

Problem might be an open circuit resistor, check them to see if they have their proper resistance as marked on the resistor body with color bands.

-Ben

 

[tunedwolf]

Did you think that the diode in the pic was a diac? :S
It only has one band its marked 1N4004

Problem might be an open circuit resistor, check them to see if they have their proper resistance as marked on the resistor body with color bands.

-Ben

No. I didn't, I'm well aware of what a BR100 looks like. Given that this a phase angle type speed control, it would be unusual for one not to be fitted, even if I can't obviously see it in the picture.