Valhalla Service Manual

Valhalla Service Manual
18th August 1999
Valhalla Service Manual
Valhalla Service Manual
Valhalla power supply for LP12 Turntable
IMPORTANT – DO NOT FAULT FIND ON THE VALHALLA WHILE IT IS
POWERED UP unless you have read the ‘Important Safety Information’
section below.
Contents
INTRODUCTION .................................................................................................................................... 2
ABOUT THE VALHALLA ............................................................................................................................ 2
ABOUT THIS MANUAL .............................................................................................................................. 2
R ETAILER & D ISTRIBUTOR OBLIGATIONS ................................................................................................... 2
HOW TO USE THIS MANUAL ...................................................................................................................... 2
INSTALLATION ..................................................................................................................................... 3
IMPORTANT SAFETY INFORMATION............................................................................................................ 3
INSTALLATION ....................................................................................................................................... 4
PLACEMENT.......................................................................................................................................... 4
POWER-UP PROBLEMS........................................................................................................................ 5
POWER UP PROBLEMS ............................................................................................................................ 5
FUSE BLOWING ...................................................................................................................................... 6
SWITCH ON & LED PROBLEMS ............................................................................................................ 7
SWITCHING & LED PROBLEMS ................................................................................................................. 7
TURNTABLE MOTOR PROBLEMS ........................................................................................................ 8
TURNTABLE MOTOR P ROBLEMS ............................................................................................................... 8
Page1
Contents
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Introduction
About the Valhalla
Introduced: 1982
How it works
At the heart of the Valhalla is a very low noise crystal oscillator, which produces a highly accurate square
wave at an exact frequency.
As the LP12 motor runs at its quietest when driven with a clean sinusoidal waveform, a precision filter is
employed in the Valhalla to remove harmonics from the square wave, leaving only a pure waveform.
The most uniform torque is delivered from the motor when both phases are driven at ninety degrees with
respect to one another and this is achieved by a ninety-degree phase-shift network after the filter. The two
resulting sinusoids drive an amplifier circuit, the outputs of which drive the two motor windings.
About this manual
This manual is designed to help you as a Linn Retailer or Distributor to repair as many Valhalla faults at your
repair centre as is practical and so provide the best possible service for your customer should a problem
arise.
This is, however a Service Manual for the Valhalla and deals almost exclusively with faults on the Valhalla
power supply. See also the LP12 Service Manual as certain faults that appear to be power supply problems
are actually caused by the turntable.
If you have any suggestions or comments regarding this manual, please contact Paul O’Neill at Linn
Products Ltd:
By E-mail
PAULO@LINN.CO.UK
By Phone
++44 (0) 141 303 5005
By Fax
++44 (0) 141 644 4262 Marked for attention of Paul O’Neill
Retailer & Distributor Obligations
Linn Specialist Retailers or Distributors are obliged to carry out the repairs in this manual under the terms of
the contract & warranty agreements. You should return a faulty product to Linn for repair, only if the fault is
not covered in this Service Manual. If a product, which is under warranty, is returned to Linn for repair and
the fault is covered in the service manual, Linn may levy a charge and this charge should not be passed to
the customer.
How to use this manual
DO NOT FAULT FIND ON THE VALHALLA WHILE IT IS POWERED UP…. Before first reading the
‘Important Safety Information’ section below.
The main body of this manual, the fault table, is designed to be as quick and simple as possible to use when
you are confronted with a faulty product and so it is arranged by fault symptom as the symptom is usually all
that you will know about the fault.
If you are unsure about the meaning of any words or phrases, look in the Glossary.
Before embarking on any Service work, you should read the Service Procedures section, as there are certain
procedures that must be followed in order to ensure the problem is resolved quickly and permanently
Table of contents & fault symptoms
Look firstly at the table of contents and find the category that covers the symptom you are seeing, then look
down the list of faults in that section until you find the symptom or symptoms that best describe the problem.
Page2
Contents
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Circumstances
Then simply follow the table along – the table specifies circumstances surrounding the fault symptom – e.g.
whether the fault is likely to be intermittent or constant, if the fault only occurs within a range of serial
numbers etc.
Possible causes
The next column details possible causes – this is effectively the most important section, probably the main
reason you are looking at this manual at all. There may be several possible causes for the symptom you
have – it is worth checking out all of these (and bear in mind that there may be more than one fault). For
some faults, simple checks are detailed that you can use to rule out the problem without replacing any parts,
whereas for other faults, the simplest way to rule out the problem is to replace the component(s) listed
Cure
Quite simply the action that you must take to cure the problem.
Installation
Important Safety Information
Lethal Voltages Present – exposed live parts.
We strongly advise that you do not to carry out any fault finding or other work on or near the Valhalla while it
is powered up – see points below.
§ If the Valhalla is connected to the mains, then it is powered up – DO NOT ASSUME that because the
switch LED is off that the Valhalla is powered down.
§ When the Valhalla is powered up, lethal voltages are present and easily accessible. While powered up,
do not touch any part of the circuitry with any part of your body or with metallic or conductive objects.
§ Some measuring instruments, such as an Oscilloscope, if grounded to the Valhalla can cause a massive
power surge, which may blow the board and/or the test equipment.
§ Only if you are very experienced with working on live circuitry and know exactly what you are doing
should you attempt faultfinding on the live circuit.
§ An isolated power supply must be used if work is being carried out on the live circuit to prevent power
surges as explained above and to lessen the danger of lethal electric shock.
Mains connections
The LP12 to which the Valhalla is fitted must be earthed – both for Safety and functional reasons.
The wires in the mains lead are coloured in accordance with the following code:
Green & Yellow
:
Earth
Blue
:
Neutral
Brown
:
Live
As the colours of the wires in the mains lead of this appliance may not correspond with the coloured
markings identifying the terminals in your plug, proceed as follows:
The wire coloured Green & Yellow must be connected to the terminal in the plug that is marked with the
letter E (earth) or the Earth symbol; or is coloured Green or Green/Yellow.
The wire coloured Blue must be connected to the terminal that is marked with the letter N (neutral) or
coloured Black.
The wire coloured Brown must be connected to the terminal that is marked with the letter L (live) or coloured
Red.
Page3
Contents
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Installation
DO NOT CARRY OUT ANY WORK ON OR NEAR THE VALHALLA WHILE IT IS POWERED UP – see
‘Important Safety Information’ section above.
Unpack the product & retain the packing for future transportation.
See LP12 Circuitry Installation Procedure for instructions on correct fitting etc.
As a Linn retailer, you are responsible for ensuring correct installation of the product. Read the Placement &
Handling information below.
Placement
Location & Environment
Do not locate near electronic products that may transmit RF, such as microcomputers, fax machines, TVs
etc, or connect them to the same mains socket as these devices. Also avoid close contact with the mains or
signal leads of such products – careful routing of the cables may be required.
It is better if possible to keep the LP12/Valhalla separate from other products to prevent its operation being
adversely affected by the heat and strong electrical field emitted by some products.
Avoid locations that have high humidity or the chance of the unit getting wet.
Avoid locations where there is a lot of dust.
Handling & general maintenance.
No standard maintenance to the Valhalla is possible or advisable.
Always handle the LP12/Valhalla with great care.
Do not carry out any work with the unit powered up – see Safety Information above.
ALWAYS take anti-static precautions when handling the circuit board, as tiny static discharges from your
body that you may be completely unaware of, can damage electronic circuitry and cause major problems.
Anti-static earth mats & wrist straps must be used when handling any of the circuit boards or any spare parts.
Page4
Contents
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Power-up problems
Important – Do not carry out any work on or near the Valhalla while it is powered up before reading
the ‘Important Safety Information’ section above
Please note - It is very important to differentiate between “powering up” and “switching on” the Valhalla. We
define “powering up” as plugging the Valhalla to the mains (if the Valhalla is connected to mains it is
powered up). “Switching on”, on the other hand comprises of pressing the switch on the LP12 to start the
platter turning.
This section deals with Power up only – Switch on is dealt with in the ‘Switch on’ section later.
Power up problems
Symptom
Won’t power up
at all
Circumstances
Constant
Possible Cause(s)
Fuse blown in unit and/or in
mains plug.
Won’t power up
Constant
Won’t power up
May be intermittent
Fuse on Valhalla is missing
or in wrong location (e.g.
Valhalla is wired for 115V but
fuse is positioned at 240V
location)
Mains lead faulty or
incorrectly wired
Won’t power up
May be intermittent
Won’t power up
Only affects older
spec Valhallas.
Some
components on
the board (near
the fuse holder)
may be blown
Page5
Contents
This fault only
occurs if a resistor
is fitted at location
R1 – on later
Valhallas, this was
replaced with a
Surge Guard
Varistor (a round
black component)
Valhalla is wrongly wired for
Mains supply being used –
i.e. mains voltage is too low.
(e.g. a Valhalla wired for use
with 240V mains being
connected to 115V mains
supply.)
Early Valhallas would
occasionally blow if there
was a surge in the mains,
destroying the Bridge rectifier
– BR1, resistor R1 and the
fuse.
Cure
Replace fuse(s) with correct
value & type.
Fuse in mains lead should be 5A.
Fuse fitted to Valhalla should be
1Amp
Ensure fuse is fitted and is
located correctly e.g. if used at
240V, locate in 240V location etc.
If you suspect a problem with the
mains lead or its connections at
either end, DISCONNECT FROM
MAINS IMMEDIATELY and
carefully check all connections. If
cable is faulty, replace it – do not
attempt to repair.
Check that the Valhalla is
correctly set for mains voltage
being used. If wrong, adjust to
correct mains setting by moving
the ‘Neutral’ (blue) mains
connection and move the fuse to
the correct location.
Replace the 3 blown parts –
available as a repair kit – Linn
part no: VAL REPAIR.
Note – the resistor is replaced
with a Surge Guard to prevent reoccurrence.
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Doesn’t power up
or
Powers up
(power LED may
or may not be lit)
but no function.
Valhalla Service Manual
Intermittent tapping or bumping
the unit makes fault
come & go
Bad connection either inside
or outside the unit.
Find and eradicate bad
connection. It may be something
as simple as a connector not
pushed fully home and may be
easily visible. If fault is
intermittent, see the Introduction
to Fault Finding (section on
intermittent faults), which can be
accessed via the Product
Information page of Linfo. If fault
is not intermittent, it may be
possible to trace the fault – again
see Introduction to Fault Finding
– Substitution & Isolation
Symptom
Fuse blowing
Circumstances
May be intermittent
Possible Cause(s)
Wrong type of fuse fitted
Fuse blowing
Mains surges
Fuse blowing
Probably random &
sporadic
Probably constant
Fuse blowing
Constant
Fuse blowing
Only affects older
spec Valhallas.
Cure
Replace fuse(s) with correct
value & type.
Fuse in mains lead should be 5A.
Fuse fitted to Valhalla should be
1Amp
Consult an electrician or your
power company
Check that the Valhalla is
correctly set for mains voltage
being used. If wrong, adjust to
correct mains setting by moving
the ‘Neutral’ (blue) mains
connection and move the fuse to
the correct location.
Replace BR1 – Linn part no:
MISS 032
Replace the 3 blown parts –
available as a repair kit – Linn
part no: VAL REPAIR.
Note – the resistor is replaced
with a Surge Guard to prevent reoccurrence.
Fuse blowing
Some
components on
the board (near
the fuse holder)
may be blown
Fuse blowing
Page6
Contents
This fault only
occurs if a resistor
is fitted at location
R1 – on later
Valhallas, this was
replaced with a
Surge Guard
Varistor (a round
black component)
Probably random &
sporadic
Valhalla is wrongly wired for
Mains supply being used –
i.e. mains voltage is too high.
(e.g. a Valhalla wired for use
with 115V mains being
connected to 230V mains
supply.)
Bridge rectifier BR1 faulty –
gone short circuit internally.
Early Valhallas would
occasionally blow if there
was a surge in the mains,
destroying BR1 (the Bridge
rectifier), resistor R1 and the
fuse.
Mains surges
Consult an electrician or your
power company
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Switch on & LED Problems
Important – Do not carry out any work on or near the Valhalla while it is powered up before reading
the ‘Important Safety Information’ section above
It is assumed at this point that you have checked that the Valhalla is definitely the cause of the fault – not a
bad connection etc, the motor or anything on the LP12. If you have not, please do so before proceeding.
Please note – It is very important to differentiate between “powering up” and “switching on” the Valhalla. We
define “powering up” as connecting the unit to the mains (this powers up the Valhalla). “Switching on”, on the
other hand comprises of pressing the switch on the turntable to start the platter turning. In this section, we
are referring only to the switching on. If the unit will not power up, this is dealt with in the ‘Power Up
Problems’ section above.)
If you are unsure whether or not the Valhalla is powered up: If the turntable will not switch on, it can be
difficult to know if the Valhalla is powered up or not. There is one simple, but rather crude & unscientific way
to check: With the Valhalla fitted in the LP12, plug the Valhalla/LP12 into the mains and leave it connected
for about 10 minutes; unplug from the mains, leave for about 10-20 seconds and then very carefully (they
may be very hot) touch the resistors R2 & R3 on the Valhalla (the 2 large red resistors beside the terminal
blocks). They should be hot. If they are not, the Valhalla is not powering up.
Switching & LED problems
Symptom
Will not switch on
Circumstances
Will not switch on
Unit powers up
okay but won’t
switch turntable
Will not switch on
Unit powers up
okay but won’t
switch turntable
Will not switch on
Switch LED dies
intermittently
Unit powers up
okay but won’t
switch turntable
Unit functions okay
otherwise.
Switch LED dead
Constant
Possible Cause(s)
Unit not powered up - See
‘Power up problems’ section
above.
Bad connection to/from
Valhalla or wires wrongly
connected.
Turntable switch faulty. Try
another switch in the
turntable if you have one, or
if you can get access to
another LP12 configured for
Valhalla, try swapping the
boards and/or switches to
ascertain which is faulty.
IC4 (switching IC) faulty.
Leg of switch LED has a
solder problem – probably
dry solder joint, but perhaps
a solder splash.
LED faulty.
Cure
See ‘Power up problems’ section
above.
Check all connections between
Valhalla, mains & LP12 – see the
LP12 Circuitry Installation
Procedure for instructions on
correct fitting etc.
Repair and/or replace switch –
Linn part no: SWITCH (you
would be forgiven for thinking that
this is a typing error etc, but be
assured this is the correct part
number)
Replace IC4 – Linn part no:
IC 021
Solder fault should be visible –
check & repair solder fault.
Replace LED – Linn part no:
MISS 052
Unit functions okay
otherwise
Page7
Contents
Copyright © 1999 Linn Products Limited. All rights reserved.
18th August 1999
Valhalla Service Manual
Turntable Motor Problems
Important – Do not carry out any work on or near the Valhalla while it is powered up before reading
the ‘Important Safety Information’ section above
It is assumed at this point that you have checked that the Valhalla is definitely the cause of the fault – not a
bad connection, a faulty motor or anything on the LP12. If you have not, please do so before proceeding – if
you can get access to another LP12, try connecting the Valhalla to it to rule out the turntable motor etc.
Turntable Motor Problems
Symptom
Turntable motor
does not turn at
all when turntable
is switched on.
Motor may buzz
or vibrate.
Turntable motor
turns very weakly
(may require a
push to get
started etc) or
may turn only for
a short time.
May work for a
while then stop &
vibrate or buzz
Turntable motor
turns backwards
May also have
low torque
Turntable motor
buzzes
(otherwise seems
to work okay)
Turntable motor
does not turn at
all when turntable
is switched on
Motor may buzz
or vibrate.
Page8
Contents
Circumstances
Switch LED lights
Symptoms may
vary.
Switch LED lights
Symptoms may
vary.
Switch LED lights
Symptoms may
vary.
Switch LED lights
Probably constant
Symptoms may
vary
Switch LED lights
May be intermittent
and symptoms may
vary.
Possible Cause(s)
R32 faulty – has gone open
circuit (usual value =
560Kohm).
Cure
Replace R32 – Linn part no:
RES 011
R32 faulty – has gone open
circuit (usual value =
560Kohm).
Replace R32 – Linn part no:
RES 011
R32 faulty – has gone open
circuit (usual value =
560Kohm).
Replace R32 – Linn part no:
RES 011
R32 faulty – has gone open
circuit (usual value =
560Kohm).
Replace R32 – Linn part no:
RES 011
One of the smoothing
capacitors has gone faulty –
C9, C10, C11, C12 & C13
Replace faulty capacitor(s) – Linn
part no: VAL 004 for all.
It can be difficult to ascertain
which capacitor is the cause
without fault finding on the
live circuit, so it is much
easier just to replace all 5
capacitors
Copyright © 1999 Linn Products Limited. All rights reserved.
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising