Alesis Adat Xt Service Manual

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Alesis adat xt service manual pdf

introduction to ADAT transfer

Alesis Digital Audio Tape or ADAT is a magnetic tape format used for the simultaneous digital recording of eight analog audio or digital audio tracks at once onto Super VHS (S-VHS) tape.

Valuable recordings. Your ADAT was packed with a complimentary Alesis S-VHS Mastering Audio Cassette. It should perform to your highest expectations. You can order more through your Alesis dealer or directly from Alesis. See the accompanying flyer for information on how to order. Superb fidelity. ADAT uses 16-bit linear analog-to-digital.

At Greatbear, we carefully restore and digitise 16 and 20-bit ADAT 8-track tapes, as well as sessions with higher track counts spanning multiple tapes.

ADAT machines

Thank you for purchasing the Alesis ADAT-XT Digital Multitrack Tape Recorder. To take full advantage of the XT’s functions, and to enjoy long and trouble-free use, please read this user’s manual carefully. HOW TO USE THIS MANUAL This manual is divided into the following sections describing the various modes of the XT. According to the manual, 'When this icon appears, it indicates that the transport is properly engaged in either playback or recording. When the XT is a slave in a multiple ADAT system, this icon will light to indicate that the tape is properly synchronized and the audio is sample locked to the timecode of the master ADAT machine.'

Like DTRS recorders, ADAT tape recorders use a video tape transport but running at a faster speed. Unfortunately most ADAT machines used a consumer tape transport that was not particularly rugged, often causing tape lacing problems which will damage tape. Only the later M20 and Studer ADAT machines used a much higher-quality transport that lasts well.

The ADAT format was based on a VHS transport, but even so - spares will not be available forever and key spares like the upper and lower head drum, while generally long-lasting will wear and need replacement.

Our ADAT machines include:

  • Alesis ADAT XT
  • Alesis ADAT M20
  • Alesis ADAT LX20

ADAT format variation

ADAT (S-VHS) open shell: tape width 12.7 mm (½ inch)

Alesis LX20 Type II and Alesis XT Type I ADAT machines

ADAT (S-VHS) cassette dimensions: 18.7 × 10.2 × 2.5 cm(7​1⁄3 × 4 × 1 inch)

ADAT risks & vulnerabilities

While ADAT machines use standard S-VHS tapes, there are some issues which are specific to this multitrack digital format:

  • The tapes run at around 4 times the standard VHS tape speed, so transports can wear out quickly.
  • While expensive new, most ADAT machines used a transport common to domestic VHS machines, which do not respond well to heavy use.
  • Direct digital transfer is preferable for making transfers, but this can be tricky without specialist hardware - especially when transferring multiple session tapes (16, 24, 32, 48 track sessions)

Alesis Adat Xt Service Manual Transfer Switch

ADAT recording history

The first ADAT machine was released in 1991 and had a major impact on the recording industry and home recording. Like the DA models released by TASCAM, a major benefit was that they could be synchronised with other machines, allowing for people to build their recording capacity 8 tracks at a time.

ADAT’s use of ½ inch S-VHS video tape meant that the larger tape width was less susceptible to damage than the 8mm Hi8 tapes used by the DA-88 and DTRS. The S-VHS tapes could record 40 minutes and because 8 tracks of audio require a large amount of bandwidth, the tape moved up to three times the speed of the average VHS tape.

ADAT is still used in some industries and the recording industry, even if it has to a large extent been replaced by Digital Audio Workstations (DAWs).

ADAT subsequently referred to the Alesis ADAT HD24-XR, which featured hard disk recording rather than the traditional tape-based ADAT (now considered obsolete), but this machine too has now been discontinued.

We are the only official ADAT repair center and have some of the only remaining original parts for ADATs in the world. If you want your ADAT restored don't hesitate to give us a call.

Alesis Adat Lx20

We think educating customers is key, so we have written a tutorial below for how to clean your ADAT transport and tape head.

Alesis Adat Brc

Manual Cleaning Procedure

Cleaning Materials

For the tape path:

Lint-free cotton buds.
DO NOT USE THIS COTTON BUD TO CLEAN THE ROTARY HEAD SYSTEM.
99.9% pure Isopropyl Alcohol - available from your local pharmacy.
For the rotary head system:

Lint-free cloth.

99.9% pure Isopropyl Alcohol.

or

CQ video head cleaning sachet.

The sachet contains a lint-free pad already dampened with the correct cleaning solutions.

WARNING!

Before proceeding, Remove The Mains Power And Other Connections To The Machine.
FAILURE TO UNPLUG THE UNIT FROM THE MAINS SUPPLY BEFORE OPENING MAY CAUSE ELECTRICAL SHOCK.
Place the ADAT facing forwards on a clear surface, remove the top cover.

Tape Path Description.

The tape is taken from the left supply hub and travels past a stationary guide, the tension arm, P1 fixed guide, impedance roller and then P2 inclined and roller guide. From there it enters the rotating head system. On exiting from the rotating heads the tape passes around P3 inclined and roller guide across the linear head and P4 fixed guide and from there through the capstan shaft/pinch roller and onto the take-up hub.

Note that the inclined and roller guides will be located at the front of the rotary head system in the unlaced or disengaged position.

Cleaning The Tape Path.

All parts that come into contact with the tape should be cleaned. Refer to the drawing as an aid to identification.

Adopt a logical approach following the path of the tape from the left of the transport towards the right. This will ensure nothing is missed.

Use a cotton swab dipped in alcohol and adopting a sideways (horizontal), rather than an up and downward motion, clean the following components:

On the left, entrance side of the transport, in order:

• Tension arm post.

• P2 Inclined post and roller guide.

• Fixed post - not shown.

• P1 Stationary guide and impedance roller.

On the exit side, in order:

• The linear head.

• P4 fixed guide.

• Capstan shaft.

• P3 inclined post and roller guide

Make sure the white roller guide sleeves are cleaned thoroughly by rotating them.

To aid identification:

• Guides incorporate a channel in which the tape runs.

• Posts have a constant diameter with no channel.

The linear head, which resembles a conventional analog head, can be cleaned with a swab, again using side to side strokes.

The capstan shaft can be cleaned with alcohol.

Do not clean the pinch roller as the alcohol will cause the rubber to become hard and crack over a period of time. Unless you have specialist rubber cleaner, leave the pinch roller cleaning until its next service.

Make sure any excess moisture is removed after cleaning.

Rotary Head Description.

There are two main parts to this, the lower drum, which is stationary and secured to the chassis and the rotating upper drum or 'scanner' which houses the two read and two write heads. The scanner rotates in a counter-clockwise direction at high speed. The heads themselves are located at the bottom of the scanner in recesses. Their alignment is critical and should not be disturbed under any circumstances. If the condition of the head has deteriorated to the point where an ERR 7 is displayed, the use of a cleaning tape may well not be enough to clear the problem.

Cleaning the Rotary Head

THE HEADS ARE EXTREMELY DELICATE AND HAVE BEEN PRECISELY ALIGNED DURING MANUFACTURE. ALTHOUGH THE OPERATION IS STRAIGHTFORWARD, IT IS VERY IMPORTANT TO EXERCISE CAUTION WHEN HEAD CLEANING AND TO PROCEED CAREFULLY AND METHODICALLY.

IF YOU HAVE ANY DOUBTS DO NOT PROCEED. CAUTIONS: WHEN CLEANING THE ROTARY HEADS.

• Do not use any material other than lint-free cloth (CQ sachet) for cleaning the rotary head.
• Do not move cloth while holding it against the head.
• Do not use upward, downward or sideways motions.

To clean the heads open the CQ sachet, which already contains the necessary cloth and cleaning agents. Leaving the cloth folded, place it against the drum (the easiest place is on the right-hand side of the drum) and hold it gently in place with your index finger. While applying GENTLE pressure to the drum rotate the upper half or scanner ANTI-CLOCKWISE 20 times, using the round rotor board that is secured to its top.

(We repeat, it is very important that you do not move the cloth or your finger while you are rotating the scanner as this can damage or affect the alignment of the heads.)

This has the effect of swiping the heads through the material and the cleaners, which dissolve out the embedded oxide and debris, depositing them onto the cloth. The result is a dark smear on the material. Continue cleaning until no more residues appear on the cloth, do not let the cloth dry out.

The helical groove around the top of the lower drum should also be cleaned. As this does not spin a cotton swab moistened with alcohol will suffice. As you clean this groove, rotate the upper drum a little to keep the heads away from the swab.

Do not allow the cotton swab to come into contact with the heads.

Wait for two or three minutes to allow the alcohol to evaporate before inserting a tape, failure to do this will result in a tape tangle.

Test the recorder while the mechanism is still exposed to be sure that the tape plays satisfactorily and that none of the indicators described in the first section of these instructions is present.

Having completed the head and tape path cleaning and tested that the recorder is operating correctly, replace and secure the top plate or cover of the ADAT, return the recorder to its normal position and reconnect the mains power, audio, and control cables.