Just acquired a Dual CS505-1 turntable made in Germany that was sold in Canada.
It is wired for a 115v 60Hz supply.
How can I adjust the wiring inside the plinth for 230v operation in the UK?
There is a small circuit board inside the plinth with 5 pins for external connections. The Dual SM100 motor has 2 identical windings. I suspect it is a 16 pole synchronous design.
Will I need a different spindle for 50Hz operation?
I have traced the existing wiring, but would rather not guess how to change it.
Nick
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If it's a DC servo motor, you won't need a different pulley. The main power transformer may or may not have facility to run directly on 230V. The AC input should be fairly basic - there could just be two wires that go directly to the transformer, with the power switch being on the DC side. A stepup transformer for a low-consumption item like a turntable should not be too expensive, if one is required.
The simplest way to convert to 230 operation is to fit a series capacitor to act as a dropper. To calculate its value you need to find the motors current consumption (on the ratings plate) and dc resistance.
To convert from 60Hz to 50Hz you either need a bigger pulley, which may be sitting there under the TT, or else to use the sellotape trick. Despite being a horrible bodge it actually works well. The idea is to wind tape round the pulley to bring its size up as needed. The tape must be cut to the correct width before winding it on, and it must be wound in the direction that results in the outer end being pressed back into place every revolution. I used this trick when younger and it does work properly. Although it may sound unattractive, its either that or run round trying to get a suitable pulley, which I doubt you'll ever find.
I have a manual for a Dual 521 which is a similar vintage turntable BUT NOT IDENTICAL so please be aware that my info might not be correct for your turntable!!!!
In the 521, the motor is easily rewired for 220-240V operation. there is a 'box' that the motor leads go to, as well as the mains leads. The mains leads got to pins 1 and 4, and remain that way. Dual usually uses brass connectors that go on pins, and can be slid off to change.
For 110-125V: Green and Black go to pin 4, Orange and White got to pin
2, pin 3 is not used, and the neon lamp for the strobe goes from pin 2 to pin 4
For 220-240V: Green goes to pin 4, Orange and Black go to pin 3, White goes to pin 2. the lamp leads goes from Pin 4 to Pin 3. (The lamp is across ONE of the motor windings, so it sees about half the line voltage.)
A NEW MOTOR PULLEY IS CALLED FOR! In the 521, the 60 Hz pulley is part number 234 454, and the 50Hz pulley is 234 253. This part will have to come from Dual, or a scrap turntable. While you are ordering parts from Dual, I'd also replace the drive belt, and the cogged speed belt, if the
505 has one.
Again, please remember that my info is for a different model than yours.
I posted a reply to this message yesterday but it did not show up on the group. I think I hit the "reply to author" button instead of the "reply" button. I didn't keep a copy of the message so I'll try and redo it for the benefit of the rest of the group.
I have the service manual for this turntable. The wiring for 115V should be as follows:
Pin 1 = No connection Pin 2 = White wire from motor plus one end of strobe wire. Pin 3 = Yellow wire from motor. Pin 4 = Green wire plus one end of capacitor which is in series with strobe lamp, plus one end of AC input, and another wire whose color is not labeled that comes from the motor. Please label this wire as "wire #4," as I'll be referring to this wire in the conversion process. Pin 5 = Other side of AC input.
The wiring for 230V should be performed as follows:
Changes to pin 1
Move green wire from pin 4 to pin 1.
Move one end of strobe wire from pin 2 to pin 1.
Move "wire #4," from pin 4 to pin 1.
Changes to pin 2
Move one end of capacitor in series with strobe lamp from pin 4 to pin 2.
White wire on pin 2 remains on pin 2.
Pin 3 has no changes. Yellow wire remains as is.
Pins 4 and 5 should now have only the AC input attached.
Make sure you double check all of this before plugging it in. If you have any questions, please ask.
The 60Hz motor pulley needs to be changed to a 50Hz pulley. The Dual part number is, 261938.
Good luck.
-- David Farber David Farber's Service Center L.A., CA
You are correct! I can't find a source of pulleys.
The pulley is a funny split thing that is forced apart with the pitch control, but I understand this only does +/- 6% so a silone rubber sleeve might work!
It might, if it happens to be just the right size. You can calculate the size you need, you want the final outer circumference to be 60/50 x the present circ.
correction, that would give you the wanted running circumference, which under slight squashage will be a mite smaller than unsquashed circumference. So you want a circumference of that much plus a mite.
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