Linn LK280 - Amplifier Problems - Fault Table; No Output from Channels

LK2 Service Manual
Page13 Copyright © 2000 Linn Products Limited. All rights reserved.
Contents Paul O'Neill
Amplifier problems – Fault Table
No output
Symptom Circumstances Possible Cause(s) Cure
No output from
both channels
Possibly
intermittent
Unit not powering up
correctly.
See ‘Power up problems’ section
above
No output from
one channel
Applies only to
LK260 & LK275
Probably constant
One of the “Reliability
Modification” components
has failed
Carry out “LK2 Reliability
Modifications” – procedure can
be accessed via Linfo – Product
Information.
No output from
one channel
OR
occasionally may
affect both
channels
May be intermittent Amp has tripped. See ‘Trip Faults’ section below.
No output from
one channel
Applies only to
LK280
Probably constant
Power transistor (the large
transistors clamped to the
heatsink) faulty.
It is sometimes possible to
measure these transistors
using an ohmmeter to check
if faulty (usually internal
short-circuit across one or
more of the junctions), but
also there is the possibility
that the transistor measures
okay but is indeed faulty.
It will sometimes be
necessary to change them to
confirm or rule out this fault.
Check / replace power
transistor(s).
Part details –
Q23 & Q30 – 2SA1386; PNP;
160V; 15A; MT100 (Linn part no:
TRAN 017)
Q24 & Q34 – 2SC3519; NPN;
160V; 15A; MT100 (Linn part no:
TRAN 018)
No output from
one channel
Applies only to
LK275 & later
versions of LK260.
Probably constant
Power transistor (the large
transistors clamped to the
heatsink) faulty.
It is sometimes possible to
measure these transistors
using an ohmmeter to check
if faulty (usually internal
short-circuit across one or
more of the junctions), but
also there is the possibility
that the transistor measures
okay but is indeed faulty.
It will sometimes be
necessary to change them to
confirm or rule out this fault.
Check / replace power
transistor(s).
Part details –
Q20 & Q27 – 2SA1386; PNP;
160V; 15A; TO218 (Linn part no:
TRAN 017)
Q24 & Q31 – 2SC3519; NPN;
160V; 15A; MT100 (Linn part no:
TRAN 018)