Origin Live DC Motor Kit - Manual (Page 6)

Page 6
• A worn thrust bearing - this may occur on a small run of bearings, which were too soft.
• Transistors that have developed temperature instability.
E X C E S S I V E M O T O R N O I S E
The motor needs a run in time of around 2 - 4 days
continuous running. They are sometimes a little noisy to
start with. Do not run the motor at full speed - use the
strobe to set the speed at around 33rpm and run in on this
setting. Most importantly you can “tune in” the motor
to give minimum noise by slackening off all 3 mounting
plate screws next to the pulley then tightening one screw
in turn. Find out which screw reduces motor noise when
lightly tightened and then adjust the other two to give
minimum noise. It may be necessary to use thread lock or
similar to stop the screws vibrating loose. If it continues to
be very noisy please get back to us and we may check it out.
However bear in mind that the dc motor is never silent as
a/c motors are - this is because they are cogless and rely on
a different type of brush. Having said this dc motors still
sound a lot better in terms of musical performance.
The other major potential source of noise is the motor
vibrating against it’s top plate and causing it to resonate.
The solution is usually to slightly tighten the 3 small screws
holding on the motor. This adjustment is fairly critical - if
the 3 small screws are too tight then the motor whispers, too
slack and the motor can vibrate against it’s top plate.
The best way to set the tension is tighten up the 3 small Phillips
screws until they just nip tight. Then back off all 3 screws a little
way. Now tighten one screw at a time till you hear which ones
cause the least noise when tensioned. You will know when the
motor is tuned as the motor noise will reduce to its lowest level.
Please note that by adjusting these screws you effect the angle of
the motor. If the belt touches the flanges at the top or bottom of
the pulley then the motor is at too extreme an angle and you will
need to re-adjust the bolts.
The ideal is for a vertical pulley with the lowest noise level.
If you get a knocking sound from the motor then slightly
slacken off the 3 screws holding the motor to the top plate.
If you have checked the above and are still having trouble
please contact us making a note of the serial number on the
back of the control box.
F I T T I N G T H E P O W E R S U P P L Y T O A N L P 1 2
To fit the DC motor kit to the Linn is very straightforward and is
accomplished by carrying out the following steps. No drilling of
the top-plate is required and the modifications are easily reversible
should you ever wish to sell your Linn but retain the DC motor.
Unplug the deck from the mains supply for obvious safety reasons
and before doing any work allow the Valhulla capacitors to
discharge for 45 minutes. Do not remove the baseboard cover
before this period is over as there is danger of lethal electric shock.
You MUST also remove the mains plug at this stage to avoid any
possibility of someone plugging it in at a later stage. You will
not need the Linn electronic power supply any more, so it can
either be detached entirely or simply left in place for quick reversal
of this modification. The LP12 will sound better if the Valhulla
board is removed entirely due to the additional resonance it inputs
to the plinth.
Unscrew the baseboard from the Linn - the screws, which hold on
the 4 rubber feet and 2 others, usually hold it on.
Disconnect the 4 wires leading to the Linn motor (2 grey, 1 blue,
1 red) by slackening the screws holding them at the terminal
block. Note the positions for each color of wire in case of needing
to refit the Linn motor.
Unscrew the 2 slotted pan head screws that control the tilt of the
Linn motor.
Unscrew the 2 black round headed Allen screws that hold on the
Linn Motor - you may need to slacken off the nuts underneath
first. This will allow you to remove the Linn motor but be careful
not to lose the 4 cone-shaped spacing washers that reside between
the top of the motor and the bottom of the stainless steel top
plate (see Fig 1). It is also recommended to remove the belt guard
as this can rub against the belt depending on how your Linn is
adjusted.
Now fit the DC motor as shown in Fig 2 below using an original
black round-headed Allen bolt and nut plus the 2 brass washers
supplied with the kit. The brass washers only serve as spacers - they
are not designed fit directly under the bolt heads. The bolt only
need to be “nipped“ tight for best sound quality and the distance
from centre of platter to motor pulley centre should be adjusted to
approx 127 - 129mm for correct belt tension (start at 127). There
are 3 holes drilled in the dc top-plate to allow extra flexibility in
positioning the motor as Linns differ slightly in dimensional set
up. For tension see also notes on wiring the power supply.
Now connect up the control box set the speed (see above) and
enjoy!