motor dismantled.DVD for scale

I've had this motor at least for 5 years (salvaged from something) and I remember it working then. However it doesn't work now (5 VDC mobile charger) and so I opened it up expecting to see just the split rings. But I was surprised to find this circuit built in it. Why does it need that circuit and what does it do? The motor body says - (If the picture is not clear) 6JS E 06 R 2400N 6V

Link to a better quality picture http://postimg.org/image/l4unckkin/

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That looks like a DC motor of the type used in tape cassette players.

Why does it need that circuit and what does it do?

For music reproduction with accurate pitch constant motor speed is required. Achieving this in battery powered equipment requires addition of a voltage regulator or speed controller as DC motors' speed varies (nearly linearly) with voltage. The potentiometer in the motor allows the speed to be factory set.

I modified one such motor on a good tape deck, adding an external pot and switch to allow some pitch adjustment so that I didn't have to keep retuning my guitar between tracks / albums.

enter image description here

The TDA1151 seems to be one simple device intended for such applications.

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  • \$\begingroup\$ With circuitry hidden inside, it becomes a non-reversible DC motor! The OP perhaps tried to run it backwards, frying the regulator IC. Easily replaced, if pn numbers are visible on the black "transistor" IC. Motor can be reassembled. \$\endgroup\$ – wbeaty Apr 21 '16 at 17:48
  • \$\begingroup\$ I had no luck working the motor by directly providing 5 VDC at the terminals that rest against its commutator and so I thought maybe the circuit is essential for driving the motor? \$\endgroup\$ – Adarsh Pryce Apr 21 '16 at 17:48
  • \$\begingroup\$ Did it ever work with 5V in the past? Maybe it's a 12 or 24V motor, with torque too low at 5V (unless completely reassembled, so the bearings are aligned right!) \$\endgroup\$ – wbeaty Apr 21 '16 at 17:51
  • \$\begingroup\$ It says 6V on the body and I thought 5 volts were close enough .It did work in the past but I don't remember how I did it. \$\endgroup\$ – Adarsh Pryce Apr 21 '16 at 17:52
  • \$\begingroup\$ Check continuity on the windings at the commutator segments and again with the brushes connected. 5 V should run it. \$\endgroup\$ – Transistor Apr 21 '16 at 17:53

Hard to see, but it has three windings, so it easily may be a brushless motor. Then the board may hold hall effect sensor, or be an encoder, or even a servo conter. I would bet on hall effect sensors.

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    \$\begingroup\$ Its the magnetic field is provided by permanent magnet which is in cylindrical shape attached with outer cover. but i am not sure there is no hall effect sensor or an encoder !!! This moro mostly used in cassette player to play the cassette. \$\endgroup\$ – Photon001 Apr 21 '16 at 17:25
  • \$\begingroup\$ I see two brushes, in the white plastic part. And on the 3-coil rotor there appears to be a 3-segment commutator just under the tiny white washer. It looks like a conventional DC motor, but probably with a voltage-regulator IC to produce fairly constant RPMs. \$\endgroup\$ – wbeaty Apr 21 '16 at 17:44

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