🔬Sony MDR-SA3000 Driver Repair

I repaired a dead Sony MDR-SA3000 driver.

The driver was not giving an ohm reading or continuity signal on a multimeter.

Fortunately, this driver is constructed in a way that it is actually possible to almost fully disassemble and repair - this is NOT recommended for most dynamic drivers, as they are all constructed differently. I also do not recommend this type of repair for most people. The difficulty level is extreme.

• Using a scalpel or small craft knife, carefully break the glue seal around the edge of the magnet housing (pictured on the right). • I did this by poking it into the glue many times, and toward the end using long cutting actions. • It can be prized out gently with a small flathead screwdriver, going around the circumference incremnetally, with not too much force. You don't want to break or dent the plastic as much as possible.

• Here you can see the voice wire, leading away from the voice coil (middle) towards the left outer edge of the driver.

• When removing the diaphragm from the front housing, it might either fall out by itself if most of the glue is already removed, or you need to apply pressure from the other side VERY gently and incrementally working your way around the edges. ❗ You ABSOLUTELY DO NOT want to bend the metal outer ring (gold coloured) as this will destroy the driver performance.

• A macro closeup of the voice wire going around the inner circumference of the driver. • The green stuff is a strange jelly like glue that is easily broken. It is similar to the stuff that sticks plastic bank cards to paper letters.

Here was my first big obstacle • The voice wires were laminated together. • I needed a microscope to separate them. • To the naked eye, this is thinner than human hair and looks like one tiny wire.

• Driver diaphragm under the microscope. • I used a brand new scalpel to separate the wires. • This was EXTREMELY difficult.

• Success.

• Now the driver should be put back into the front housing grill. • Then remove ALL the glue from the electrical contact pad area. • The voice wires need to go through this tiny gap that is filled with glue. • A needle file will be very useful here. • Pay CRITICAL attention to the pressure being applied around the magnet housing as you push the driver 'sandwich' back together. • If the sandwich is not 'flat' with a correct seal between all pieces, there will be distortion.

• Here I extended the contact pads towards the edge of the driver with 2 single strands of speaker wire (basically oxygen free copper strands). • Then I carefully soldered the voice wires to the copper strands. ❗ Solder did not work alone. For some reason, only once I covered both contacts with electronic silver paint did the solder make a reliable connection.

Click here to see the final measurements. As you can see, there repaired right channel has almost zero deviation from the left. I do not claim this to be a professional repair, as the tolerances are not as precise as those in the Sony factory assembly line. But it actually works nearly perfectly and sounds fine, and that's enough for me.