Linn LK85 Service Manual page 9

nd
2 June 1999
Stand-by Problems
Information about the Stand-by facility
Stand-by on these amps should work as follows:
§
On leaving the factory, the amp is set to automatically go into stand-by if no signal is detected for 10
minutes.
§
The Stand-by timing can be adjusted by moving a link inside the amp – it can be set to go into stand-by
after 10 or 20 minutes.
§
The above Stand-by facility can be over-ridden by moving the link to 'on' – this means the amp will stay
on and never go into stand-by.
§
Early units' stand-by was configured differently – Stand-by could be set to 'stand-by' (unit goes into
stand-by after about 15 minutes if no signal is sensed) or 'on' – unit stays on & does not go into stand-
by.
§
If the unit is in stand-by and a signal (music) is sensed at the input, it comes out of Stand-by
§
The sensitivity of the input signal sensing can be adjusted. Maximum sensitivity means that the amp will
come out of stand-by if even a very quiet level of music signal is detected. This level of sensitivity can
sometimes cause problems if there is noise (hum, hiss etc) in the system – the amp may never go into
stand-by or may come out of stand-by when it shouldn't. Minimum sensitivity means that it takes an
extremely high volume level of music to bring the unit out of stand-by. Usually closer to Max sensitivity is
preferable and adjust if this causes a problem.
The following table contains problems you may encounter with the 'Stand-by' facility on the LK85/LK140.
Stand-by Problem Table
Symptom Circumstances
Amp goes into Probably
stand-by while intermittent,
music is playing. depending on what
type of music is
played and how
loudly it is being
played.
Unit never comes Probably constant
out of stand-by.
The above Stand-
by faults have been
ruled out.
Unit never comes Probably constant
out of stand-by.
The above Stand-
by faults have been
ruled out.
Unit never goes May be intermittent
into Stand-by, no
matter how long it
is left with no
music playing.
Unit never goes Probably constant
into Stand-by, no
matter how long it
is left with no
music playing.
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Contents
Possible Cause(s)
Sensitivity is set to minimum
(or close to minimum) on
affected channel(s).
Monolithic IC(s) (U100,
U101, U200, U201) blown.
Please note – U100 & U201
are only fitted to the LK140
U1 and/or U2 faulty – pulling
'stand-by' line down.
Sensitivity is set to maximum
and noise in the system
(hum, hiss etc) is preventing
the unit going into Stand-by.
Internal adjustment link (near
the centre of the board,
adjacent to the large
capacitors) is set to 'ON'.
This is the setting that
disables the stand-by
function.
Copyright © 1999 Linn Products Limited. All rights reserved.
Cure
Adjust sensitivity closer to
maximum.
It is advisable to replace the
entire board, as blown
monolithics often destabilise the
board – repair is not normally
reliable.
Replace faulty part(s) – Linn part
nos:
U1 - IC 132
U2 - IC 362
Adjust sensitivity.
Move link to '10 mins' or '20 mins'
depending on how quickly you
wish the unit to go into stand-by.