[SOLVED] Help with circuit debugging

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shariq92

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Hello everyone.
Some time ago the button my electric shaver jammed. When my brother opened it, its button had melted on the inside could not be moved. Since i did not see the button before it was thrown out, i do not know which terminals connect to turn the motor on. I made a schematic of it. If anyone can help me out i would be grateful.

I have tried the following combinations
2-4 Current reaches 2.2 Amperes and the wire starts to get hot.
i know this shouldn't have any effect but i still tried it.
1-4 no current draw.
3-4 no current draw.
 

with 2-4 the battery is connected directly to the motor. With that current and no turning the motor is
Short circuited, stuck or both. Which was probably the cause that the switch melted.
In that condition there is no point in replacing the switch.
 

Err, it could just be that the battery is flat. Connect 3 to 4, this is the motor is OFF but the charging circuit is connected. Plug it into the mains charger and leave for a good few hours (14?). then disconnect from the mains open 3 to 4 and short 1 to 2. the motor should start.
Frank
 

Thanks for your replies guys.
@albert22 while trying out random combinations my hand slipped and the motor turned on momentarily but i couldn't note the connections because my hand slipped (i was trying to read the current on my multimeter.)
@chuckey the battery is able to supply over 2 Amps so i think the battery can't be dead. But still i am going to try your solution and reply back on the thread.
 

Sounds like the motor commutator is damaged which resulted in the switch getting burned out. Since it may only be damaged in one position and random bump or rotate may get it started , but is probably n.g.
I am not sure if there is an additional switch not shown to block running the shaver if the charger is connected but pin 4 to 2 or 1 ought to supply power. and 1 to 2 to charge 3 doesnt matter but can be connected to 1 to show charge voltage present..
 
Thanks for your input.
The shaver used to run even when the adapter was connected so no switch there.
So does that mean the shaver is scrap now?
 

Reading SunnySkyguy's comment i checked the motor by opening it and found that one of the brushes touching the commutator was smaller than the other. When i adjusted it a little and connected the motor to power, the motor turned on. However, the motor stopped working when i tried again. So any advice? Should i replace the motor or should i try to put something else in its place like a wire or something??
 



According to your circuit, you should have following connections:

1 and 3 - for charging (can be permanent connection),
2 and 4 - for motor running,
Switch is between 2 and 4.

Check state of brushes, or try to replace it.

Clear gaps of commutators with needle.

Try to find to replace motor first, then try replacing commutator in case that commutator is problem.


Replacing commutator (see all steps) :
**broken link removed**
 
Last edited:
Ok so the problem was solved. Thanks everyone for taking the time to help me out.
The problem was that one of the commutator brushes had been worn out and was not touching the commutator. I took a tinned wire and hammered it a little to flatten it. Next i simply replaced the brush with that flattened wire. For now it seems to be doing the trick but i suppose i should look for another solution such as replacing the motor.
Thanks to all of you again.
 

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