Philips CDM VAM CD Lasers Types - Deep Dive

Philips CDM VAM CD Lasers Types - Deep Dive

Introduction

The Philips CDM lasers are widely used optical pickup mechanism in CD players, CD-ROM drives, and other optical disc players. This laser mechanism is responsible for reading the data stored on the disc and translating it into the audio or digital information that we hear or see. In this article, we will take a closer look at the Philips CDM laser, its construction, working principle, some of its unique features, and common faults associated with it. 

Table of contents

  1. Construction
  2. Working principle
  3. Unique features
  4. Philips Laser Types

Construction

The Philips CDM laser consists of several key components that work together to ensure accurate data reading. These components include the laser diode, photodiode, collimator lens, and objective lens. The laser diode generates a coherent beam of light that is focused onto the disc surface by the collimator lens. The objective lens then focuses the reflected light onto the photodiode, which converts the light signal into an electrical signal that is processed by the player's electronics.

The laser diode used in the Philips CDM is a semiconductor device that emits light when an electrical current is passed through it. This laser diode is typically made of gallium arsenide and emits light in the infrared range. The collimator lens is a small optical element that ensures that the laser beam remains collimated, or parallel, as it travels towards the disc surface. The objective lens is a more complex optical element that focuses the reflected light onto the photodiode with high precision.

Working principle

The working principle of the Philips laser is based on the reflection of light from the disc surface. When the laser beam hits the disc, it reflects off the pits and lands on the disc surface, creating a modulated reflection. This modulated reflection is then focused onto the photodiode by the objective lens, where it is converted into an electrical signal.

The laser mechanism is equipped with a servo system that adjusts the height and position of the objective lens to ensure that the laser beam remains in focus and centered on the disc surface. This servo system also compensates for any disc wobbling or warping that may occur during playback, ensuring smooth and uninterrupted data reading.

Philips VAM CDM Laser Optics 1205 1206 1250 1254

Unique features

The Philips laser mechanism is known for its unique features, which make it a popular choice for CD players and other optical disc players. One of its most notable features is its high precision and accuracy, which enables it to read data from even the most damaged or scratched discs. The laser mechanism is also very efficient, consuming very little power and generating minimal heat during operation.

Another unique feature of the Philips laser is its ability to read multiple formats, including CD-DA, CD-ROM, and CD-RW. This versatility has made it a popular choice for a wide range of applications, from consumer CD players to professional CD mastering systems.

 

Types

Philips has produced several generations of CD player laser mechanisms over the years, including the CDM and VAM families. These laser mechanisms differ in their design, construction, and specifications, and are not always compatible with each other or with all types of CDs.

CDM and VAM laser mechanisms share some similarities, as they both use a laser diode to read the digital information stored on a CD. However, they differ in their construction, as well as in the types of optical components and electronic circuits used to control the laser beam.

CDM laser mechanisms were introduced in the early 1980s, and were used in many of Philips' early CD players. The CDM family includes several different types of laser mechanisms, which are identified by a three-digit number that indicates the model and version of the mechanism. For example, the CDM-1 mechanism was one of the earliest and most widely used models, while the CDM-9 was a later and more advanced design.

VAM laser mechanisms were introduced in the mid-1990s, and were designed to improve on the performance and reliability of the earlier CDM models. Like the CDM family, the VAM family includes several different types of laser mechanisms, which are identified by a four-digit number that indicates the model, version, and variant of the mechanism. For example, the VAM-1201 was one of the earliest and most widely used models, while the VAM-1250 was a later and more advanced design.

In general, VAM laser mechanisms are designed to be more precise, faster, and more reliable than CDM mechanisms, and are often preferred by audiophiles and music enthusiasts for their superior performance. However, not all CD players are compatible with all types of VAM mechanisms, and some players may require specific versions or variants of the VAM mechanism in order to work properly.

Exploded View Philips VAM 1205 1254 1206 1202 CDM

Philips CDM Types

Philips is a well-known brand that has been producing high-quality audio equipment for decades. One of its most significant contributions to the audio industry is the Compact Disc (CD) format, which was developed in collaboration with Sony in the early 1980s. Philips also developed a series of Compact Disc Modules (CDMs) that are used in CD players from various manufacturers. These CDMs use laser technology to read the data stored on CDs.

The first Philips CDM was the CDM-0, which was introduced in 1982. Since then, Philips has developed several other CDM models, each with its own unique features and capabilities. Here are some of the most common Philips CDM laser types and their compatibility:

  1. CDM-0 – This was the first CDM model developed by Philips. It uses a helium-neon laser and has a resolution of 16 bits. 
  2. CDM-1 – The CDM-1 was introduced in 1984 and was an upgrade to the CDM-0. It uses a semiconductor laser and has a resolution of 16 bits. 
  3. CDM-2 – The CDM-2 was introduced in 1987 and was designed for use in portable CD players. It uses a semiconductor laser and has a resolution of 16 bits. 
  4. CDM-3 – The CDM-3 was introduced in 1989 and was an upgrade to the CDM-2. It uses a semiconductor laser and has a resolution of 16 bits. 
  5. CDM-4 – The CDM-4 was introduced in 1987 and was designed for use in home audio systems. It uses a semiconductor laser and has a resolution of 16 bits. It is compatible with most CD players.
  6. CDM-9 – The CDM-9 was introduced in 1994 and was designed for use in high-end audio systems. It uses a semiconductor laser and has a resolution of 16 bits. 
  7. CDM-12 – The CDM-12 was introduced in 1999 and was an upgrade to the CDM-9. It uses a semiconductor laser and has a resolution of 16 bits.
  8. CDM-12.1 – The CDM-12.1 was introduced in 2001 and was an upgrade to the CDM-12. It uses a semiconductor laser and has a resolution of 16 bits. 
  9. CDM-12.4 – The CDM-12.4 was introduced in 2004 and was an upgrade to the CDM-12.1. It uses a semiconductor laser and has a resolution of 16 bits. 

Common faults

Like any mechanical device, the Philips laser is prone to some common faults. The most common fault is the failure of the laser diode, which can lead to a complete failure of the laser mechanism as it is not able to focus on the CD surface and read the data. This will mean your CD player will not read discs and may display ERR or Pause on the display. The CD may also spin backwards or forwards at a high speed. All these symptoms are indicative of a laser diode failure that will require the laser to be replaced.

Behaviour in player

Upon player startup and once play button is pressed the following procedure is completed by the laser mechanism, monitoring this sequence on your player can help you understand where the fault is occurring.

 

  1. Laser moves to the centre of the CD disc.
  2. Laser will power on and attempt to find focus on the CD surface with the objective lens by cycling the laser lens up and down relative to the disc surface until focus is obtained.
  3. Once focus is achieved, the spindle motor will be powered on and laser will read CD track list and store it in memory.
  4. Laser will begin playing track 1 and CD drive will spin up to required speed.

The most likely failure in this process is step two where the laser will not obtain focus on the disc surface. you may be able to see the laser moving up and down in the mechanism before CD error /  ERR / pause is displayed on the player. This may also coincide with CD spinning backwards on some models as the electronics get confused.

If the laser diode has failed the solution is to replace the CD laser pickup in the mechanism. On our site we offer replacement laser pickups and repair instructions. Some products we sell will cover full player disassembly, instructions, specific tools and the required lasers to resolve you issue.

Players we provide full instructions for include:

  • Beosound 9000 MK1 MK2 MK3
  • Beosound 2000
  • Besound Century

Player we will provide replacment lasers for and instcution on how to replace the laser in the mechanisim include:

Pelase use search bar to find specific laser for your player.

    Please message us if you do not see a specific listing for your player.

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