This documents the elimination of the soft/flat switch functionality on a Martin Logan CLS IIz electrostatic speaker.
NOTE: This hardware potentially contains high voltages! Do not work on an energized unit! Exercise extreme caution with a recently de-energized unit. The units I worked on were de-energized/cold (both AC and audio input) for at least 24 hours prior to modification. Work safely. Consider yourself warned.
Click on any of the pictures below for a full-resolution version.
This is the unit to be modified, lid has been removed.
This is the flat/soft switch. Pull the spade terminals with a
needle-nosed plier. In the "flat" position, the switch is closed.
In the "soft" position it is open.
When the switch is in the "flat" position, it shorts out the RC network
to the left of the wires from the switch. The owner of these speakers
never uses the "soft" position. Let's just jumper it over and take
any effects of this wire, switch and spades out of the equation. Note
that the photo orientation is from the left side of the unit as viewed
from the rear of the chassis.
Remove the board.
De-solder the wires to the switch. I used a double-twist of bare
silver coated copper to make the connection. Clip the excess wire
flush on the bottom of the board.
Carefully replace the board back in the chassis.
Not shown here, but I opted to replace the wires on the switch terminals,
clip the ends to prevent potential shorting issues, and then tucked the
leads around the right-side of the transformer, just in case it needed to
be put back in service at some point.
Before you close up, ensure that everything has been reconnected, no leads are shorted, no clipped wire ends remain and that no tools are left behind.
This page last modified Thu Apr 21 15:58:42 CDT 2011 by timc!