To remove the turntable on the HMV Imperial you need to first remove the amplifier component by removing screws underneath cabinet. Once screws removed, lift amplifier out carefully part way until you can get your hand underneath and disconnect the 3 joining Leeds. One for power, one for speakers and maybe one aerial. Once all wires disconnected lift unit out with power lead still attached. Once unit is clear you can get your hand underneath to turn the mounting clips on the turntable to vertical position. Once clips at vertical, turntable lifts out.
A turntables speed can be affected when components deteriorate.
Records sound distorted. In replacing any part, use an exact duplicate
or a substitute that is recommended by the manufacturer.
A turntable platter rotates at 78, 45, or 33 and 1/3 revolutions per
minute by direct drive(a drive wheel and rubber rollers) or by belt
drive.
. To check the speed, chalk a point on the edge of a record and one
on the chassis near the platter. Line them up, and then turn on the
record player. Clock how many times the two points meet during 1 minute.
Remove the platter by prying the c-clip from the spindle with
needle-nose pliers and lifting the spindle out, then lift the platter
from the chassis.
On a direct drive, the drive wheel is held to the chassis by a
c-clip that clutches a drive shaft. While grasping the clip with the
needle-nose pliers, pry it from the shaft with a small screwdriver.
Normal 0 MicrosoftInternetExplorer4 Don't forget the positions of the
washers above and below the wheel so that you can replace them
correctly.
To replace a belt, remove the turntable platter and wrap a new belt
around the pulley and the rim under the turntable platter. Reinstall
the platter.
Remember to always use care when servicing anything that uses electricity; always unplug before removing or replacing any part.
Even if your turntables belt is stretched it may need to be replaced
because it can have an effect on the quality of the sound. Just these
few replacements could turn an old record player into tip top shape.
Turntable
Setup
General
Most turntable companies provide reasonably good
instructions for the proper setup and operation of their products. But
sometimes, these instructions are not very clear, or are translated in a
peculiar way. Hopefully, this section will remedy some of the questions that
come up during turntable setup
The Platter
Direct Drive
For
direct drive turntables, place the platter over the spindle and lower into
place gently. There is usually a strong magnetic force that will pull the
platter into place. Be prepared for that and lower the platter gently into
position on the spindle. Now. place the mat on top and this step is complete.
Belt Drive
There are 2 kinds of belt drive. dual platter designs and
single platter designs. In the dual platter design the 2 parts are the drive or
inner platter and the top platter. The drive platter is permanently part of the
turntable body. The drive belt runs around this platter and the motor pulley.
Install it now if required. Now place the top platter in position, then the top
mat and this step is complete.
In a single platter
design, there must be a way to contain the belt when installing the platter. If
you look under the platter, you will see an inner ring running around the
middle third of the platter. The belt should be already installed by the
factory there. If not, do it now. The belt will stretch and stay in place. Now,
place the platter over the spindle. You should notice a hole in the the top
platter. Align this hole over the motor spindle. Now, reach in and pull the
belt across to the motor pulley. Now place the top mat and this step is
complete.
Cartridge Mounting
Standard Mount Style
Some
turntables come with the cartridge already mounted. This makes life easy. But
if you are changing the cartridge or simply need to mount it, here are the
details.
You will need:
I will use the procedure we follow here for
Stanton cartridges and Technics Head shells, the process is basically the same
for other tonearm designs.
Use the self threading plastic slip on nuts, they
prevent electrical grounding of the cartridge body to the headshell. This can
be a major cause of ground loop hum. Slip the nuts onto the cartridge mounting
flange wings.
FIRST, REMOVE THE NEEDLE AND
PLACE IT OUT OF THE WAY
Now, hold the
cartridge in place against the bottom of the head shell and insert a screw
through the top of the head shell and into the self threading nut. Use the
screwdriver to start this screw. Once started, insert a screw in the remaining
side and start it too. Snug each screw into place a little at a time, until
they are just almost home. Leave the cartridge slightly loose so it can move
back and forth in the slotted openings.
NOW, INSERT THE NEEDLE, BUT FROM HERE ON BE VERY
CAREFUL
Now slip the overhang gauge onto the
back of the head shell and use your eyes to sight down the tip of the gauge.
Move the cartridge in the slots until the stylus tip is just in line with the
end of the gauge. This is the proper location for the cartridge. carefully
tighten only one of the screws and re check to see that the overhang is still
correct. Now, remove the gauge , and looking a the outline of the cartridge
body against the headshell outline, slightly rotate the cartridge body until it
is square with the head shell outline. Now tighten the remaining screw and
recheck. If all is correct, replace the stylus
guard and this step is now complete. If your turntable does not have
an overhang guage, you will have to seek out an aftermarket alignment gauge or
protractor.
P-Mount
Style
P-Mount or T4P style tonearms are very easy
to install cartridges into. The tonearm terminates in a square socket and will
usually have a single screw on the right hand side. Remove the screw. Take the
P-Mount cartridge and insert it into the mating tonearm socket. Be sure it is
inserted all the way (The screw will not go in unless the cartridge is fully
seated.) Insert the screw and tighten snug. Since P-mount cartridges and
tonearms are designed to install with perfect alignment, there is no alignment
procedure. This step is now complete.
Cartridge Wiring
If you have
some DeoxIT or ProGold contact enhancer. apply it now to the cartridge pins.
If you are using the Technics original head shell, you
must open the connections slightly to make attachment easier or risk breaking
them. If you look closely at the connectors at the end of each wire, you will
see that they have a slot that runs the full length. Grasp the connector at its
rear(where the wire is crimped) with the needle nose pliers, and push the screw
driver blade into the opening just a little to widen the slot. Do this to all 4
wire connectors.
Now, select a wire, Grasp the connector at its rear(where
the wire is crimped) with the needle nose pliers, and push it on to the
cartridge's matching color connector. If there seems to be too much resistance,
go through the spreading operation described above and open the connector up a
little more. Attach the 4 wires and this step is complete.
Tonearm Setup & Adjustment
First, insert the headshell into the tonearm. Most tonearms use
a bayonet pin style collar locking mechanism. The pin is on the headshell.
insert the headshell, pin facing up, into the end of the tonearm. Holding the
headshell in position with one hand, rotate the knurled collar nut on the back
of the tone arm, and you should see the head shell being drawn into the
tonearm. Tighten snug. (Note: never remove the rubber washer on the end of the
headshell. it is important.).
Locate the counterweight. Slip it onto the
back of the tonearm and push it all the way forward. You should be able to read
the counterweight dial scale from the front of the turntable
Now,
remove the stylus guard, and unlock the the
tonearm from its rest.
Holding the tonearm lightly against the rest with
one hand, begin rotating the counter weight clockwise. The weight will be
moving towards the rear. Keep checking the condition of the tonearm at the arm
rest. You will reach a point where the tonearm just begins to lift off of the
arm rest. STOP turning the counterweight, This is the
Zero position..
Now, lock the arm back down. Hold the chrome part of
the counter weight with one hand and turn the dial scale to read zero. Friction
coupling will keep the dial set properly.
Now, turn only the chrome part of
the weight counterclockwise until the scale reads the desired tracking
force.
Set the anti-skate setting to the same number as
the tracking force.
The Tonearm
Height
If your turntable has a tonearm height
adjustment, set it this way.
Place an old record on the turntable and cue
the needle down in the center, It need not be turning.
Now come down so that
your eye is level with the platter. Sight the tonearm from the left or right
side of the turntable. Does the tonearm wand appear parallel to the record? It
must be to perform it's best. Make a note of the condition (too high, too low.)
and adjust the tonearm height as required to achieve this condition.
Finding The Best
Location
Few turntables made today have springy
suspensions. Therefore today's tables are more sensitive to foot falls. The
best location for a turnable is a wall mounted stand. This will eliminate
problems from floor bound vibrations. Home centers have good wall shelf systems
that work very well and are adjustable
Connecting The Turntable
The
turntable will have a left signal wire, a right signal wire and a electrical
ground wire. Connect these to your stereo or phono preamp. Connect the ground
wire to the screw provided or, if no screw was provided, then loosen a chassi
screw and use that. The ground wire is important in minimizing
hum.
I'm Hearing Alot Of
Hum!
This is the most common problem encountered
with phono playback systems. And it can be puzzling sometimes to track down.
First, you must isolate the source. Is it :
The Stereo
The Phono Preamp
The Turntable Wiring
The Phono Cartridge
The
Stereo
Switch the stereo to CD or AUX, and
with nothing playing, turn the volume up to your normal listening position. If
there is no hum now, then we can eliminate the stereo. If there is a hum,
powersupply service is probably indicated.
The Phono
Preamp
This will require one accessory, a
shorting plug. You need to get a couple of standard RCA plugs from Radio Shack
for instance, and you need to short the center pin to the outside ground. Now,
in place of the turntable, plug the shorting plugs into the phono input. Now,
set the stereo to phono and turn the volume up to your normal listening
position. If there is no hum now, then we can eliminate the phono preamp or
phono stage. If there is a hum, phono stage service is indicated.
The Turntable
Wiring
This will require one accessory. a pair of
alligator clips. You can also get these at RS. You need to clip together, I.E.
short out the left and right cartridge pins. Do this on the back of the
cartridge. You needn't remove the cartridge connections. Just connect one pair
of clips between the red and green pins and another between the white and blue
pins. Now, set the stereo to phono and turn the volume up to your normal
listening position. If the hum is gone now, then we can eliminate the turntable
wiring. If there is a hum, something is amiss with the turntable wiring. either
a bad connection. or perhaps someone has changed the factory wires for some
"fancy" wires that do not give sufficient shielding.
The Phono Cartridge
If
you've come this far, then the problem must be the phono cartridge.
Most
cartridges use hi permeability steel shells to protect the coils from
electrical fields that can cause hum. However, not all companies use this
system. As such , there are some cartridge brands that are sensitive to
external electric fields and will hum. The only solution you have is to replace
the offending cartridge. Or, if you love the sound and want to keep it, you
will have to play with the location of the turntable and try to minimize hum.
Sources of hum fields are power transformers in equipment, wiring in the walls,
certain turntable drive motors. Experiment by listening to the hum while you
move the tonearm through its arc(cued up!!) and see if you can find a null
location that will give you the best results.
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