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Old 6th Dec 2017, 4:22 pm   #2
rtbcomp
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Join Date: Aug 2007
Location: Sheffield, South Yorkshire, UK.
Posts: 50
Default Re: Decca Deccalian Motor Mounting Replacement.

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6) Note the relative positions of the motor and its mounting plate and undo the three screws holding the motor to its mounting plate, these are tapped into the motor, there are three spacers and washers which will most likely be embedded in the gunge that was once the mounting grommets. Clean all the gunge off, I used a sharp chisel.

Putting it back together:

1) Acquire

3 off grommets 6mm
https://www.beal.org.uk/electrical-p...mmets-6mm.html

2 off grommets 9mm
https://www.beal.org.uk/electrical-p...mmets-9mm.html

6 off M5 Washers
https://www.beal.org.uk/hardware-fas...m-bzp-500.html

2) Slice the 9mm grommets in half so that they form rubber washers.

3) Install the new washers/grommets and original screws/washers/spacers like this:

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The bits in blue are the new grommets; green, the original fixings and purple the M5 washers.

1) Fit the motor to the plate, don't forget the spacers, these are essential, if you omit them there is a risk that the screws will screw in too far and damage the motor windings.

2) Re-assemble it all but don't fit to the deck, fit the idler (don't forget the brass spacer, no need for the circlip yet)

3) Check the clearance between the bottom of the idler and the top of the 78rpm pulley on the motor shaft:

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If there isn't enough clearance move one of the M5 washers from above the motor plate to below, this will lower the motor slightly relative to the idler.

4) When the clearance is OK assemble it all, less the idler, and install back on the baseplate using the 2 screws and nuts furthest away from the speed-change link, leaving them slack, omit the screw nearest the link.

5) Raise the short link on the assembly away from the deck and insert the pivot peg. Slide some folded paper between the deck and the head of the peg, this will stop it moving when fitting the link.

6) Fit the 3rd screw and tighten up

7) Refit the motor switch, insert it in its hole and fit the knurled nut so it's flush with the top of the threaded boss then screw the hexagonal nut up to secure the switch. Note it's orietnation so that the lever points forward when switched on.

At this point it's worth paying some attention to the speed-change control, mine was gunged up with dried grease.

1) Remove the knob by pulling upwards

2) Remove the circlip from below the knob and push the shaft downwards through its bush.

3) Clean all the grease off and re-assemble, a drop of light oil should be applied to the shaft prior to inserting it into the bush.

4) Fit the end of the link to peg, fit the circlip and remove the paper.

5) Lightly oil the rubbing surfaces of the speed-change mechanism

6) Re-fit the idler & circlip, putting a drop of oil on the shaft

7) Put a drop of oil in the turntable bearing and refit the turntable.

8) Tighten the grub screw then turn it back a full turn, check the turntable runs free and won't lift off. If there was a 2nd grub screw tighten it up against the first one to lock it.

9) Re connect the motor supply and pickup connector

At this point it may be a good idea to slip some sleeving on the rubber wires carrying mains to the motor and the two switches, I used spiral binding as this can be fitted without disconnecting the wires.
https://www.beal.org.uk/electrical-p...0mm-x-25m.html


Refit the deck:

1) Lower it vertically so the springs seat in the pockets on the side runners, it may be necessary to move the deck about a bit to get the springs to locate correctly.

2) Check the turntable runs quietly on both speeds.

3) Refit the front and rear fillets

4) Release the tone arm and refit the pickup.
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