2.2.1.1.4 Deterioration by replay

Unlike mechanical carriers, fairly modern and well preserved magnetic tape can be replayed several hundred times without any measurable loss of quality. However, a pre-condition is well maintained replay equipment of the latest generation, which allows gentle handling of the carriers. Older or poorly serviced machines may severely damage, if not destroy, a tape during replay.

2.2.1.1.4.1 Alignment and maintenance of equipment (replay only). Magnetic tape players need careful alignment of the following parameters:

• vertical position, azimuth, and wrapping angle of replay head (Whenever head adjustment has to be changed to compensate for errors of the recording head of a given recording, it is imperative that the heads be re-aligned to their correct settings immediately after the playback is completed.);
• vertical position of tape guides to ensure horizontal tape travel and to avoid asymmetrical position of tape packs on reels and open hubs;
• calibration of tape tension in the play and winding modes, particularly if thin (amateur) and brittle cellulose acetate tape is to be played;
• alignment of the replay amplifier according to speed and equalisation standard (Alignment is head-dependent, therefore changing head blocks for different track formats will require re-alignment of the replay amplifier, or amplifiers switchable to different pre-settings.).

Maintenance comprises:

• the cleaning of tape heads and tape path (Frequency of cleaning is dependent on the abrasiveness of tapes in use. All surfaces of the tape path must be kept in perfect condition in order to avoid any scratching of the tape surface (2.2.1.1.3) as well as to avoid irregular speed fluctuations and to guarantee smooth tape-head contact.);
• frequent (daily) demagnetising of tape heads and tape guides (3.7.2.1.1);
• complete check of alignment and recalibration every 50-100 hours playing (not running) time.

The keeping of logbooks for each piece of equipment and the careful documentation of all alignment and maintenance work is imperative (IASA-TC 04, 5.4.)