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Provides an overview of the Valhalla's technical features and functionality.
Explains the purpose, scope, and intended audience of the service manual.
Outlines the responsibilities for Linn retailers and distributors regarding repairs.
Guides users on effectively navigating and utilizing the information within the manual.
Crucial warnings regarding electrical hazards and safe handling practices during servicing.
Details the correct wiring and connection of mains power for safety and functionality.
Advises on selecting an optimal location and environment for the unit's operation.
Troubleshooting guide for issues where the unit fails to power on or initialize.
Diagnoses common faults related to blown fuses and their potential causes.
Troubleshooting issues related to the unit's power switch and LED indicator status.
Guides on diagnosing and resolving malfunctions with the turntable motor.
Provides an overview of the Valhalla's technical features and functionality.
Explains the purpose, scope, and intended audience of the service manual.
Outlines the responsibilities for Linn retailers and distributors regarding repairs.
Guides users on effectively navigating and utilizing the information within the manual.
Crucial warnings regarding electrical hazards and safe handling practices during servicing.
Details the correct wiring and connection of mains power for safety and functionality.
Advises on selecting an optimal location and environment for the unit's operation.
Troubleshooting guide for issues where the unit fails to power on or initialize.
Diagnoses common faults related to blown fuses and their potential causes.
Troubleshooting issues related to the unit's power switch and LED indicator status.
Guides on diagnosing and resolving malfunctions with the turntable motor.
The Valhalla Service Manual provides comprehensive information for Linn Retailers and Distributors on repairing the Valhalla power supply, an essential component for the LP12 Turntable. Introduced in 1982, the Valhalla's primary function is to deliver a highly accurate and clean power supply to the LP12 motor, ensuring optimal performance. At its core, the Valhalla utilizes a very low noise crystal oscillator to generate a precise square wave. Since the LP12 motor operates most quietly with a clean sinusoidal waveform, the Valhalla incorporates a precision filter to remove harmonics from the square wave, resulting in a pure sinusoidal output. To achieve uniform torque from the motor, both phases are driven at a ninety-degree angle relative to each other. This is accomplished through a ninety-degree phase-shift network located after the filter. The two resulting sinusoids then drive an amplifier circuit, whose outputs power the two motor windings of the LP12.
This manual is specifically designed to enable Linn Retailers and Distributors to perform Valhalla repairs at their service centers, thereby offering prompt and efficient customer service. It focuses almost exclusively on faults related to the Valhalla power supply. However, it also advises consulting the LP12 Service Manual, as some issues that appear to be power supply problems might actually originate from the turntable itself. The manual's structure is designed for quick and easy use, with fault symptoms serving as the primary entry point for troubleshooting. Users are encouraged to first consult the table of contents to locate the category that matches the observed symptom, then identify the specific fault or symptoms that best describe the problem.
A critical aspect of using this manual involves understanding the "Important Safety Information" section before attempting any fault finding or work on the Valhalla while it is powered up. This section highlights the presence of lethal voltages when the Valhalla is connected to the mains, even if the switch LED is off. It strongly advises against touching any part of the circuitry with body parts or conductive objects while powered up. The manual also warns that grounding certain measuring instruments, such as oscilloscopes, to the Valhalla can cause massive power surges, potentially damaging both the board and the test equipment. Fault finding on a live circuit is only recommended for highly experienced individuals who fully understand the risks and procedures. If live circuit work is necessary, an isolated power supply must be used to prevent power surges and minimize the risk of electric shock.
The manual also outlines important installation and handling procedures. It emphasizes that the LP12, with the Valhalla fitted, must be properly earthed for both safety and functional reasons. It provides a color-coding guide for mains lead wires (Green & Yellow for Earth, Blue for Neutral, Brown for Live) and instructions for connecting them to the appropriate terminals in a plug. Users are advised to unpack the product carefully and retain the packaging for future transportation. For detailed instructions on correct fitting, the LP12 Circuitry Installation Procedure should be consulted. As a Linn retailer, ensuring correct product installation is a responsibility.
Regarding placement and environment, the Valhalla should not be located near electronic products that emit RF, such as microcomputers, fax machines, or TVs, nor should it be connected to the same mains socket as these devices. Close contact with mains or signal leads of such products should be avoided, and careful cable routing may be necessary. Keeping the LP12/Valhalla separate from other products is recommended to prevent adverse effects from heat and strong electrical fields. Locations with high humidity, risk of getting wet, or excessive dust should also be avoided.
Maintenance features for the Valhalla are minimal, as no standard maintenance is possible or advisable. The manual stresses the importance of handling the LP12/Valhalla with great care. Crucially, no work should be carried out on the unit while it is powered up, reiterating the safety information. Anti-static precautions are mandatory when handling the circuit board, as static discharges can cause significant damage to electronic circuitry. The use of anti-static earth mats and wrist straps is essential when handling circuit boards or spare parts.
The troubleshooting section is divided into categories such as "Power-up problems," "Fuse blowing," "Switch on & LED problems," and "Turntable Motor Problems." Each section presents a table with symptoms, circumstances, possible causes, and cures. For instance, under "Power-up problems," if the unit "Won't power up at all" and the symptom is "Constant," possible causes include a blown fuse in the unit and/or mains plug, or a missing/incorrectly located fuse on the Valhalla. The cure involves replacing fuses with the correct value and type (5A for mains lead, 1Amp for Valhalla) and ensuring the fuse is correctly fitted. If the Valhalla is wrongly wired for the mains supply being used (e.g., 240V Valhalla connected to 115V mains), the cure involves checking and adjusting the mains voltage setting by moving the 'Neutral' (blue) mains connection and the fuse to the correct location.
For older Valhallas, a surge in the mains could destroy the Bridge rectifier (BR1), resistor R1, and the fuse. The cure involves replacing these three blown parts with a repair kit (Linn part no: VAL REPAIR), noting that the resistor is replaced with a Surge Guard to prevent recurrence. Intermittent power-up issues or issues where the unit powers up but has no function might indicate a bad connection inside or outside the unit, requiring identification and eradication of the faulty connection.
In "Switch on & LED problems," if the unit "Will not switch on" despite powering up, possible causes include bad connections to/from the Valhalla or wrongly connected wires, a faulty turntable switch, or a faulty IC4 (switching IC). Cures range from checking all connections and replacing faulty cables to repairing/replacing the turntable switch (Linn part no: SWITCH) or replacing IC4 (Linn part no: IC 021). If the switch LED dies intermittently, a solder problem (dry joint or splash) is a likely cause, requiring a check and repair of the solder fault. A dead switch LED when the unit otherwise functions okay indicates a faulty LED, which should be replaced (Linn part no: MISS 052).
"Turntable Motor Problems" addresses issues like the motor not turning at all, turning weakly, turning backwards, or buzzing. Common causes include a faulty R32 (open circuit, usual value = 560Kohm), which should be replaced (Linn part no: RES 011). If the motor does not turn at all and symptoms are intermittent, one of the smoothing capacitors (C9, C10, C11, C12 & C13) might be faulty. Since it can be difficult to pinpoint the exact faulty capacitor without live circuit fault finding, replacing all five capacitors (Linn part no: VAL 004) is recommended as an easier solution.
The manual also includes a glossary for unfamiliar terms and emphasizes reading the "Service Procedures" section before undertaking any service work to ensure problems are resolved quickly and permanently. This structured approach, combined with clear safety warnings and detailed troubleshooting steps, makes the Valhalla Service Manual an indispensable resource for maintaining the optimal performance of Linn LP12 Turntables.
General| Output Current | 1A |
|---|---|
| Type | Power Supply |
| Mains Input | 220 - 240 V |
| Output Frequency | 50-60Hz |
| Input Voltage | 100-240V |
