18
th
August 1999
Valhalla Service Manual
Page2
Copyright © 1999 Linn Products Limited. All rights reserved.
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
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
‘
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.
