Linn LK260, Руководство по обслуживанию

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LK2 Service Manual
Page2
Copyright © 2000 Linn Products Limited. All rights reserved.
Contents
Paul O'Neill
Introduction
About the LK2 Series
There were three versions of the LK2:
•
The first version was known at the time simply as the LK2. It gave an output of 60 watts per
channel (into 8 ohm load) and used PCAS 003 type boards. For the purposes of this manual, we will
refer to this version as the LK260.
•
The second type was also usually known as the LK2 but was often called the LK275 to differentiate it
from the 60-watt version, as it gave 75 watts per channel. Also used PCAS 003 type boards but with
several improvements over the 60 watt version – the most obvious being the increased power output, but
also had improved protection circuitry and better sound.
•
The third and last type was known universally as the LK280. 80 watts per channel – used PCAS 020
boards. PCAS 020s, at first glance are similar to PCAS 003s, in that they are roughly the same size,
shape and layout, but they are a completely different design of board (i.e. not just a modified version of
PCAS 003) as a closer examination shows. The LK280 sounded considerably better than either of its
predecessors.
How to differentiate between types of LK2
There are several methods of determining the specification of an LK2:
•
Looking at the serial number of a unit and using the LK2 Product History (accessible via Linfo
website – Product Information) will tell you which revision it was sold as. Since, however upgrade kits
were sold by Linn in large quantities to allow customers to convert their early version LK2 into the latest
spec, many units are not what they seem. The following information will help you to determine the
specification of a unit if its exact history is unknown.
•
LK280s had “LK280” printed on the facia – earlier units (LK2 & LK275) had “LK2” printed there, but
beware – an earlier version may have been upgraded to LK280 spec.
•
LK260s and LK275s had a red power LED and LK280s had a green LED. This is handy as a quick
and easy indicator but is not 100% reliable (LEDs are easily changed)
•
The best way to determine a unit’s spec is simply to remove the sleeve and look at the boards that
are fitted (see below).
Distinguishing Features of Different Board Types
PCAS 020 – used
in LK280
Small heatsink bar
with transistors fitted
to it – found on PCAS
020 only Capacitor &
resistor (bridged)
not fitted to 60
watt board These diodes and
capacitors not fitted
to 60 watt boards
PCAS 003 – used
in LK260/LK275
60 watt type used same board
but with some differences, as
shown below
Small “Hybrid” board
fitted here at 90 degrees
to main board – found on
PCAS 020 only