Idiomas disponibles
Idiomas disponibles
20
SGM 10A/12A/15A
Servicing
Cleaning the cabinet
To remove marks and scuffs, use a medium soft brush. If necessary,
a little warm water and detergent can be used, but under no
circumstances use a solvent or abrasive cleaner. The surface will
change colour when wet but will return to normal when dry.
Dual Concentric driver removal
Before any servicing operation, the amplifier should be disconnected
from signal input and mains power. Lay the cabinet on its back, taking
care to protect the rear plate. Remove the four hexagonal bolts and
set aside. Ease the driver from the front of the cabinet, taking care not
to mark the front surface.
Use a piece of stout cardboard to lever against if necessary. Remove
the driver and disconnect the internal wiring, taking care not to
damage the moving parts of the LF driver.
To refit the driver, connect the cables from the wiring harness to the
LF (red +ve and blue -ve) and HF (white +ve and black -ve) terminals.
Fit the driver into the mounting hole, fasten the bolts finger tight and
then progressively torque them down so that the driver seats evenly.
Drive unit servicing
The HF unit may be fitted with a new diaphragm assembly. With the
driver face down, release the three bolts securing the HF assembly
and lift the HF unit vertically upwards and away from magnetic
attraction caused by the LF magnet. Replace the diaphragm - it is
self-centering - taking care to align the parts correctly.
To refit the HF unit, hold it about 30 cm vertically above the LF
magnet in both hands while resting on your elbows. Slide your elbows
apart and lower the HF unit onto the back of the LF magnet. As the
HF unit gets close to the magnet you will feel the magnetic fields
repelling. Align the fixing holes and secure with the bolts, tightening
down evenly. Do not tighten the bolts finally until you are sure the HF
unit is seated correctly and the two magnet systems appear parallel.
The LF unit may be re-coned in the normal way. Use only the parts
and adhesive supplied in the re-cone kit.
Checking the unit
The whole unit can be checked using a sine wave generator
connected to the input. A high quality, low distortion (preferably a
beat frequency) oscillator will be required to check for any buzz and
rattle noise generated by the drive unit. The voltage to be applied at
the input should be 0.2 Vrms. Testing the whole unit has an obvious
drawback in that, in the case of any defect it may be difficult to
determine whether the drive unit or the amplifier is faulty. In which
case each part would have to be checked independently, meaning
that the drive unit should be removed (refer to above).
If for whatever reason the amplifier needs to be removed from the
cabinet, care should be taken to remove only the relevant screws
(there are 8 mounting screws, 2 on each side of the plate).
Fuse
A fuse is located just under the mains input. Replacement is simple
and a spare fuse is provided inside the fuse housing itself. Always use
the correctly rated fuse, as indicated on the silk screen printing, there
are two different types according to the operating voltage.
Any other servicing regarding the electronic section should be
undertaken by qualified and authorised personnel only.
In case of any malfunction of the unit, the first thing to be checked
should be the input connection, especially if the source has
unbalanced outputs as improper connection can result in significant
level reduction and affect the response.
21
Quick Start Guide
