Service manual

Chapter 3
Major Parts & Disassembly
The Quad ESL is relatively easy to disassemble, but care should be taken not to
damage the thin front grille and not to damage the panel dust covers if they are not
going to be replaced. The first step is to remove the three wooden feet, this is done
by gently laying the speaker on it’s front grille on any padded surface. The feet
are held to the frame by four wood screws each. The feet are typically punched
with the a letter on the contact area of the foot to indicate it’s proper position on
the frame. When the speaker is placed face down, the foot marked “R” is actually
on the left when facing the bottom of the speaker, similarly the foot marked “L” is
located on the right side. The center rear foot is not marked.
After the feet have been removed, the speaker can be tipped up onto the base
of the frame. The wooden side panels (or trim panels) can then be removed, this is
shown in figure 3.1. Many speaker left the factory with screws for the side panels
that are too long and actually screw into the sides of the bass panels. In some cases
this damages the panels. IT is advised to either buy slightly shorter wood screws
or grind an eighth to a quarter of an inch off the end of each screw. After the bass
panels have been removed, the sides of the panels can be inspected to determine
of the trim screws are too long.
Before the front and rear grilles can be removed, they must be disconnected
from the power supply ground. There are a pair of bare wires that connect the
front and rear grilles tot he power supply. These are located under the frame base
and are shown being cut in figure 3.2. Rather than cutting these wires, they can
also be unsoldered from the eyelets on each grille.
After the grounds have been removed, the back grille can be removed by un-
screwing the screws around the parameter of the grille. The rear grille can then be
carefully removed from the frame.
After the grille is removed, all the basic components of the ESL can then be
clearly seen. An ESL with the rear grille is shown in figure 3.3. The assembly
on the right frame base is the bias voltage power supply and is also shown in
figure 3.4. This power supply will be described in mor detail in the power supply
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