The Mike New Bearing Base Plate

[ChrisKemp]

Any bearing base plates left, Mike I sent you an email...

[Mike_New]

Yes I currently have 2 available at this time and one more blank to be machined.
These may be the last as it is not sensible to keep on making one-offs every 6 weeks or so.

[Mike_New]

Instructions for Bonding the Bearing Base Plate to the SL1200
Issue:-- 3 (01-04-14)

Note: These Instructions should be read and understood before proceeding with fitting the Bearing Base Plate.

Every effort has been made to ensure that these Instructions are clear and unambiguous; follow them carefully.

Note: These Instructions assume that the customer has replaced the Technics Power supply with an External Power Supply and that the old transformer and small circuit board have been removed. Also that the customer has fitted my ‘High Precision Bearing’

Tools required:
a) Posidrive screwdriver to remove the three black bolts that hold down the coil assembly and bearing. (a Phillips screwdriver may be used with care.)
b) Allen Key to fit the new 1/8” Whit bolts for the bearing and coil assembly.
c) 10mm or 3/8” drill
d) Power Drill (optional)
e) Soldering Iron (to remove PS wires if required)
f) Clean workbench on which to carry out this exciting task, the kitchen work-top is ideal!!! (check with she who commands)
g) Large soft towel (to protect Platter top)
h) Smooth file (without handle)
i) Sheet of course sand paper or emery cloth.
j) Araldite Two Part High Strength Epoxy
k) Acetone or Metholated Spirits

Disassembly

a) Remove all power from the SL1200 before proceeding

b) Remove the top Hinged cover if you have one

c) Clamp down the Tone Arm and fit cover to stylus.

d) Remove the platter by inserting fingers into the two holes and pulling upwards.

e) Remove the five screws holding the large black cover (with radial slots for ventilation) remove the cover.

f) Carefully remove the three plugs attached to the cable forms from the main circuit board. One on each side of the board, (top, bottom and right hand side, when viewed from above.) Note: you may need to clip the cable clamps on the bottom cable form to give more freedom.

g) Now unsolder the wires, which come from the external power supply to the circuit board. Mark which is positive and which is negative. If it is a ‘Time Step’ power supply, the Negative (earth) should be connected to the bottom left hand corner of PCB. (If this is not the case, it should be relocated to this position on re-assembly.) The positive will be connected at the top of the board, note the position for re-soldering. In the case of the ‘KAB’ PS the DC power is connected to the two pins at the bottom left hand corner of the PCB. next to the big capacitor.
In the case of the Paul Hynes power supply, you will need to decide the best way to disconnect the wiring depending on the options you have.

h) Now remove the three self-tapping screws, which hold down the circuit board (Top Right, Bottom Right, and Bottom Left hand corners.) Use the correct size Posidrive or Phillips screwdriver.

i) Now remove the three long screws equally spaced around the motor coil assembly, these are black in colour. (these screws clamp the coil assembly and bearing to the main chassis.)

j) Carefully lift the circuit board upwards and remove the Bearing from the bearing cavity while observing how the bearing housing fits into the three curved slots of the main circuit board.

Note: You may be fitting the Base Plate to an SL1200, which already has my High Precision Bearing. In which case the following Instruction are valid also.

If you are fitting my Bearing and Bonded Base Plate as a kit, which replaces the original bearing; then the following procedure must be carried out.

With small side-cutters or nail scissors carefully trim the component wires that poke through on the soldered-track side of the circuit board, in the area of the circular body of the new bearing housing. Nip the wires neatly to immediately above the solder dome. There will be three sets of 6 wires.

Installation of the Bearing and Bearing Base Plate.

a) Firstly we need to remove the top surface of the three lugs, which protrude above the level of the chassis at the edge of the bearing well where the three bolts fit. This is easily done, by using the 3/8” (10mm) drill, to drill them out. You can either use the drill in the hand by twisting as you push down, or use a power drill, remove just enough to make them level with the bottom of the chassis.

b) Now with the file laid flat onto the surface, clean off any rough parts to the work just done.

c) Place the three long tensile bolts into the holes and screw down until they protrude below the bottom of the Base Plate by about 2mm

d) Place the Base Plate onto the cast alluminium alloy chassis so that the three protruding bolts on the underside of the Base Plate locate into the three holes in the lugs, which you have just leveled off. Make sure that the arrow marked “TOP” is pointing to the rear of the chassis. (the top is when looking down onto the unit)

e) NOTE: There may be some instances where the old Power supply has been left in position. In which situation the Base Plate will be prevented from locating correctly by the transformer and small circuit board. If you are adamant that you require to leave the old power supply in position then you will need to cut away that part of the Base Plate which interferes with the power supply. The Base Plate has been designed for maximum effectiveness as it is, cutting some of it away is not the preferred option!!

f) Now with the base plate located in position by the three protruding bolts, mark around the base plate with a felt pen.

g) Remove the Base Plate and proceed to totally remove the grey paint inside the circle with course sand paper or emery paper.

h) NOTE: On some chassis’s there may be lettering molded into the die-casting which falls within the circle marked out in (f) above. Remove this lettering with a Dremel grinder or the sharp end of a file. A sharp knife will also do the job.

i) Remove the three bolts in the base plate and set to one side.

j) Now Clean the underside of the Base Plate and the chassis area with Acetone.

k) Insert the bearing into the central hole of the Base Plate. Make sure which is the top surface of the Base Plate.

l) Now position the Base Plate so that the arrow is facing away from you and place the PCB onto the bearing, ensuring that the three Bearing posts correctly locate into the slots in the PCB.

m) Now insert the three long bolts supplied into the holes in the coil assembly lamination stack and lightly tighten.

Note: Coat the end of the threads with Vaseline before inserting.
You will now have the PCB, Bearing and Base Plate securely held together.
There should be about 1mm of thread protruding from the bottom of the Base Plate.

n) Now mix an amount of Extra Strength Araldite Epoxy Resin, making sure that equal amounts are used. Coat the bottom of the chassis within the circle you marked out, with a thin layer of epoxy resin.

o) Now coat the underside of the Base Plate with a thin layer of Epoxy.

p) Now carefully place the PCB, Base Plate and Bearing assembly into the bearing well of the chassis. Lightly press down and twist to seat the Base Plate onto the Epoxy.

q) Now ensure that the three holes in the corners of the PCB accurately align with the three locating posts in the chassis. This ensures that the Base Plate is correctly positioned over the bearing well and located centrally in the chassis. (You should be able to feel the ends of the three long bolts which protrude from the bottom of the Base Plate locate into the original holes around the Bearing Well)
(Try doing this before you apply the epoxy so that you know what you are doing.) The three supplied self tap screws can be inserted into the holes and lightly tightened to ensure the correct location.

When you are happy that the Base Plate is located correctly, do not disturb for 24Hrs.

r) The PCB and Bearing can now be removed from the Base Plate and a coating of Vaselene applied to the flange of the Bearing (where it sits on the Base Plate) before re-assembly, then tighten up the three long bolts progressively until fully tightened.

s) Using the three brass spacers, fit these to the three corner holes on the PCB, with the spacers underneath the board. There must be an earth connection lead to the bottom left hand corner position, do not forget this!! If the self-tap screws are not long enough, then obtain some longer ones (usually they are OK)

t) Now re-solder any power connections that were previously removed.

u) Now refit the three cabling plugs into their respective sockets on the main PCB

v) Check that the external power supply is correctly connected

w) Replace the platter and check that it rotates at the correct speeds. If this does not happen then you have an electrical connection problem of some sort. Carefully check all connections.

x) Before final running, add three or four drops of the bearing oil supplied, to the top of the bearing.


Final Considerations

The new Base Plate will have radically altered the VTA setting, so you will now need to reset your arm before spinning some vinyl.

The platter needs to be carefully leveled in all directions for maximum benefit. A short level placed on the platter will give the best results. Rotate the platter and check for level in all directions.

Note: The standard feet on the SL1200 are a loose fit in their threads and are unsuitable for the best results. Tightly screw all four feet into the base as tight as possible. Now use shimming to level the platter, pieces of plastic, cardboard etc will do the job. Alternatively use the ‘Isonoe’ feet, which provide excellent support.


GOOD LISTENING

[ChrisKemp]

A video of the whole prosess would be a big help. I will order after new year, Mike! I just loved what the ETP platter did to the sound in my set up! With the base plate and maybe a ebony armboard will be the final two pieces

[Mike_New]

The one thing that you have to be careful of, is to ensure that the threaded holes in the base plate are exactly on top of the original holes in the small boss's. This will ensure that the Bearing and coil assembly (PCB) is positioned correctly.
I guess a video would be useful, but so far no one has had any real problems.

[jostber]

A video of the whole prosess would be a big help. I will order after new year, Mike! I just loved what the ETP platter did to the sound in my set up! With the base plate and maybe a ebony armboard will be the final two pieces

There is a picture series with detailed descriptions in the first page of this thread.

[Mike_New]

Hi Folks,
The picture series referred to by Jostein is now obsolete and no longer relevant.
The Base Plate is now fixed to the chassis with epoxy glue, which make it a much easier method. Able to be carried out by almost anyone.
The SL1200 chassis assembly does not need to be dismantled and the tone arm can remain in place.
I should have caught up on this correction a long time ago, sorry about that, perhaps it should now be deleted.

[CableMaker1]

Hi Folks,
The picture series referred to by Jostein is now obsolete and no longer relevant.
The Base Plate is now fixed to the chassis with epoxy glue, which make it a much easier method. Able to be carried out by almost anyone.
The SL1200 chassis assembly does not need to be dismantled and the tone arm can remain in place.
I should have caught up on this correction a long time ago, sorry about that, perhaps it should now be deleted.

You mean... my instructions are no longer valid????

Sniff Sniff....
Sobb Sobb....

[Mike_New]

I posted my comments on this over a year ago.
Where have all the people gone long long ago!!!

[RobbieGong]

Get the bearing base plate if you've only got the bearing - the base plate provides an ideal platform for the precision MN bearing, allowing it to perform to it's optimum