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BOOKSHELF The DAT Technical Service Handbook The DAT Technical Service Handbook, by Richard Maddox. Published 1994 by Van Nostrand Reinhold, New York. Hard covers, 224 pages, 235 x 156mm, ISBN 0-442-01423-6. Price $109.95. Not a book for the beginner, this text is more for the person who has been carrying out maintenance or service on analog or video tape recorders and who now wishes to gain some knowledge of Digital Audio Tape (DAT) recorders. The Author was introduced to his first DAT machine in 1989 and has been concerned with maintaining them ever since. The book is divided into nine chapters plus three appendices. Chapter 1 traces the development of digital audio tape from 1983 when the Sony RDAT (rotary head DAT as i n V C R ’s ) w a s s e l e c t ­ ed as superior to the SDAT format (ie, stationary head DAT as in analog tape recorders) due among other factors to tape size, recording time and error correction. This chapter also discusses the origin of DAT copy protection, consumer versus professional decks and the tape format. Chapter 2 covers DAT recording specifications, the track section identification, the rotary transformer which gets the information from the spinning heads to the electronics, methods of head switching, automatic track finding (ATF), servo systems which keep the heads spinning at 2000 RPM for record and playback but allow small variations under the control of ATF and finally, brief coverage of analog-to-digital and digital-to-analog con­verters. Chapter 3 gets into the nitty-gritty of maintenance and service, which 44  Silicon Chip is what the book should be all about. The Author covers the tools, test tapes and equipment necessary to do the job adequately. He stresses the necessity for regular maintenance and the critical nature of the alignment of the tape path, as each track is only 1/10th the width of a human hair. He also lists the items that need regular replacement. Chapter 4 covers alignment procedures, including tape ten­sion, capstan adjustment, RF record and playback. It also in­ cludes a summary of the different alignment tapes available. Chapter 5 discusses the mechanical side of the DAT machine: the transport mechanism, head drum maintenance and wear, dismantling and reassembling transport mechanisms and some replacement pro­cedures for specific models. Chapter 6 is probably the chapter of most interest to our readers. It covers the signal flow through the recorder, starting with the analog inputs, analog-to-digital (A/D) con- version, signal pro­ cess­ ing blocks, digital-to-analog (D/A) conversion, RF circuit details and servo circuits. The Author finishes the chapter by saying that although the information was for the Panasonic SV-3900 it is mostly applicable to the SV-3700 as well. Also the transport and much of the control circuits discussed are used in the Panasonic SV-3200 and Technics SV-DA10 recorders. The Studer D-780DAT uses the Technics transport and Studer electronics. Chapter 7 covers fault finding and as is the case with electronic equipment that has a complex transport mechanism, this usually causes most of the problems. Richard Maddox has found DAT recorders are no exception. The major problem, in his experience, is tracking incompatibility between machines due to misalignment and head wear. Chapter 8 is headed “Errors And Other Causes Of Headaches”. Because the tape is moving at 0.32 inches per second (about 8 mm per second – yes, it’s an American book) and recording 61K bits per inch (approx 2400 bits per mm), you can well imagine how critical the alignment is and how a little wear could cause problems. Chapter 9 covers servicing tips for various models includ­ing Aiwa, JVC, Marantz, Panasonic, Studer, Tascam and Technics machines. For anyone maintaining one or more of these machines, the book could be a wise investment. The book finishes with three appendices. The first covers DAT abbreviations, as these will not be familiar to the beginner (eg, ADLRCK – Analog to digital left/right sample clock; and MASH – Multistage noise shaping). The second is a DAT glossary and the last, a bibliography. To sum up, this is not a book for everyone but those in the field will benefit from it. Our copy came direct from the pub­lishers, Thomas Nelson Australia, 12 Dodds Street, South Mel­bourne, Vic 3205. Phone (03) 685 4111. (R.J.W.)