Quote:
Originally Posted by keithinuk
Thank you for your information, gratefully received.
The drive is as per your picture, the speed control pot seems to be fast or slow, but has no adjustment in-between, it doesn't look like its a Speed control inside more like it's just a switch.
Is it a 60's machine?
Thanks again.
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Yes, this type of machine came onto the market around the early 1960s and improvements were made that lead to the evolution of better machines with more facilities & functions.
As to the Speed Control, when turning the adjustment knob the affect is not always immediate nor does it give a massive affect as it only controls the amount of battery power (from the C Cells) to the motor. Therefore the range can be affected by the voltage of the battery/batteries and the effeciency of the motor and moreover, the speed the original recording was made at.
For best use of the Speed Control and to get the best affect of it's speed range, when recording always set the position of the control knob to mid-way and that way, when playing back, it will have a better plus & minus range.
I've done a rough draft of a typical speed control (the underside) to show how basic it is (see pic). Usually it only has two connecting wires, one from the 1.5V battery/batteries and the other (in some way) to the motor.
The wirewound surface is a bobbin wound low resistance - uninsulated wire to which a wiper makes contact and this, when turned by the control knob, varies the resistance value in series to the motor. Therefore, as the wire surface is bare and open to the elements, it can become corroded or dirty. Therefore, using Servisol S10 to clean the surface is ideal (spray the S10 onto a cloth or cotton bud) and rub it over the wire surface.
Also, a good contact by the wiper to the wirewound surface is essential.
Tony