Problem with Dremel-style rotary tool

[Makatas]

Good afternoon! This is my first post in here and I wish I get some help because I really need it.

I happen to own a rotary tool which is like the Dremel ones, but is not a Dremel. I am satisfied with how it works.
Two months ago I bought a second, because I want to ship it to a friend abroad. So, I got it, I opened the box and tried it, and when I saw that it works flawlessly, I put it back in its little plastic case, supporting it with bubbles etc.
Weeks later, the rotary tool arirved at its destinations, but it is not working properly. What it does:
At speeds 1,2 and 3 it barely turns. At 4,5 and max it turns but will sotp when it meets any kind of resistance. As you understand, it cannot do anything even to the softest things. It really stops and has no torque.
Me and my friend tried to troubleshoot it, she has some technical skills and I aided with mine. She checked the brushes, removed and put back in, then replaced with the back-up ones, it didnt work still. She opeend the case and checked for possible problems with the speed switch or anything, sitll the thing is brand new. It really hasnt worked at all, so I dont know what the problem could be.
Could you please give some suggestions on it?
Thank you all

 

[shortbus=]

You don't give any hint to where either of you live, so it makes it hard to diagnose. Does your country and hers use the same mains voltage? If you bought it in a country that has 220V mains and she lives where mains are 110V that could be the problem.

 

[Makatas]

Sorry about it. I live in Greece, 230V 50Hz, she lives in Philippines, 220V 60Hz, according to wikipedia I just checked. I also googled and seems like universal motors do not care much on frequency (I reckon rotary tools got inexpensive universal motors?)
We can rule out the possibility of damaged electricity socket too, she tried it in many.

 

[SABorn]

I dont know if it would make a difference, but some of these cheap variable speed tools use a wave chopper to control the speed and that might be effected by the line frequency.
Most certainly the motor will not be effected but the speed controller could be.

Also some countrys have more than 1 mains voltage (220 and 110) so would pay to check with her if it is actually 220 volts she is using.

Pete.

 

[Makatas]

Thanks for your thoughts, I have been there and I know its 220 V setup.
Your idea on wave chopper seems understandable thing is I dont know how she could make the thing work

 

[KeepItSimpleStupid]

This is probably a frequency issue with the speed control.

 

[OlPhart]

Since Dremels' are simple brush DC equivalent motors, swap it for the direct on/off version and use a locally available dimmer for speed control.

I've found the Dremel speed controllers' somewhat lacking, having burnt 2 under reasonable, Not extreme, load. Did as stated above and saved $ by stopping buying theirs'.
G.H. <<<)))

 

[Makatas]

Thank you all for your suggestions.

 

[KeepItSimpleStupid]

I agree with OLP. You can also internally disable the dimmer and use a local dimmer externally. I did that with a real Dremel because I didn't like the way it was designed inside and it made no sense to have it repaired. A foot switch can also come in handy. At the present time, the modified Dremel is a spare.