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BOOKSHELF Servicing Personal Computers Servicing Personal Computers, by Michael Tooley, B. A. Pub­lished 1994 by Newnes, distributed by ButterworthHeinemann Australia. Hard covers, 387 pages, 240 x 170mm, ISBN 0-750-61757-8. Price $68.95. In this age of personal computers (or PCs as they have become known), many users, while not necessarily wanting to repair their own, will be keen to have a better understanding of the “innards” of their computer. This book will certainly en­lighten them. The first of the eight chapters in this book begins with an introduction to microprocessors, detailing the different modules that make up a typical computer. It then goes on to discuss the evolution of the home computer, beginning with the release of the 4004, a 4-bit processor, by Intel in 1971. Subsequent proces­sors of note are then listed, through to the Intel 80486 and Motorola 68030. A couple of pages are then devoted to a discourse on pro­gramming, mentioning both assembly and high-level languages. RAM (Random Access Memory) is then covered in some detail, after which brief details are given of keyboards, serial I/O (input/output), RS232 interfaces, raster scan displays and final­ly SCSI (Small Computer Systems Interface) controllers. The second chapter covers the selection of a suitable work­shop site and the consideration that should be given to work­ benches, storage, lighting, 88  Silicon Chip security and safety. A list of the basic tools required for competent service is given along with an extended list, although I believe that every workshop should consider the extended list to be the minimum. Tooley then gives a list of the minimum test equipment which would be required to set up a workshop with adequate facil­ities, then an extended list which would add many dollars to the cost. A short discussion follows on the methods of using multi­meters, oscilloscopes, logic probes, logic pulsers and logic analysers. Chapter three covers general fault diagnosis at three lev­els: basic, intermediate and advanced. Basic level skills are defined as being able to locate blown fuses, faulty cables or failed hard disc drives. Intermediate skills would allow the technician to locate intermittent connectors, faulty discrete components or a failed processor. Those possessing advanced skills would be able to locate intermittent problems, temperature faults and bus conflicts. The balance of the chapter is devot- ed to fault finding techniques for the CPU (Central Processing Unit), video circuits and RS-232 interface. Chapter four introduces the reader to tape and disc drives. Some of this material is rather antiquated (tape recorders using Kansas City recording standards) but if one is to make a living servicing computers, this know­ledge could be useful. The evolution of floppy discs is traced from the 8-inch though the 5.25inch to the current 3.5-inch types. As well, technical informa­tion is listed for a number of popular drives. The author then gives a description of the original IBM 8-inch format, which is still the basis for formatting current floppy discs. Details of several floppy disc controllers are included as well as methods of fault diagnosis for floppy disc drives. The balance of this chapter is devoted to hard disc drives, including formatting, partitioning and the use of the DOS FDISK program. Chapter five is devoted to printers, which, being mechani­ cal devices, require routine maintenance to keep them operating at peak performance. The author introduces dot matrix printers and explains how the print head actually prints a character, then lists the sensing mechanisms needed to keep track of the head position. A two-page table of dot matrix printer faults and repair procedures follows. A few lines are then devoted to the operation of laser printers and details of the self-test procedures which should be carried out to determine the cause of any failure. Routine main­ tenance and a one-page fault finding guide complete this chapter. “Displays” is the title for chapter six, which surprisingly only covers raster scan displays. A raster scan is one that uses a cathode ray tube and deflection coils to move the electron beam across the face of the tube, as distinct SILICON CHIP SOFTWARE Now available: the complete index to all SILICON CHIP articles since the first issue in November 1987. The Floppy Index comes with a handy file viewer that lets you look at the index line by line or page by page for quick browsing, or you can use the search function. All commands are listed on the screen, so you’ll always know what to do next. Notes & Errata also now available: this file lets you quickly check out the Notes & Errata (if any) for all articles published in SILICON CHIP. Not an index but a complete copy of all Notes & Errata text (diagrams not included). The file viewer is included in the price, so that you can quickly locate the item of interest. The Floppy Index and Notes & Errata files are supplied in ASCII format on a 3.5-inch or 5.25-inch floppy disc to suit PC-compatible computers. Note: the File Viewer requires MSDOS 3.3 or above. ORDER FORM PRICE ❏ Floppy Index (incl. file viewer): $A7 ❏ Notes & Errata (incl. file viewer): $A7 ❏ Alphanumeric LCD Demo Board Software (May 1993): $A7 ❏ Stepper Motor Controller Software (January 1994): $A7 ❏ Gamesbvm.bas /obj /exe (Nicad Battery Monitor, June 1994): $A7 ❏ Diskinfo.exe (Identifies IDE Hard Disc Parameters, August 1995): $A7 ❏ Computer Controlled Power Supply Software (Jan/Feb. 1997): $A7 ❏ Spacewri.exe & Spacewri.bas (for Spacewriter, May 1997): $A7 ❏ I/O Card (July 1997) + Stepper Motor Software (1997 series): $A7 POSTAGE & PACKING: Aust. & NZ add $A3 per order; elsewhere $A5 Disc size required:    ❏ 3.5-inch disc   ❏ 5.25-inch disc TOTAL $A Enclosed is my cheque/money order for $­A__________ or please debit my Bankcard   ❏ Visa Card   ❏ MasterCard ❏ Card No. Signature­­­­­­­­­­­­_______________________________ Card expiry date______/______ Name ___________________________________________________________ PLEASE PRINT Street ___________________________________________________________ Suburb/town ________________________________ Postcode______________ Send your order to: SILICON CHIP, PO Box 139, Collaroy, NSW 2097; or fax your order to (02) 9979 6503; or ring (02) 9979 5644 and quote your credit card number (Bankcard, Visa Card or MasterCard). ✂ from LCD and other newer solid state displays. Tooley starts by explaining the require­ments for a video monitor and the reasons why a normal TV set is unsatisfactory. This is followed up with a block diagram of a monochrome monitor. He continues with details of the colour shadow mask tube and the procedure for making colour adjustments. The chapter concludes with two pages of display faults and their cures. Chapter seven covers servicing of 68000 based microcomput­ers. Computers that use this chip include the Apple Macintosh, the Sinclair QL, the Atari ST and the Commodore Amiga. The sec­tion devoted to each of these products includes a block diagram of the computer, a memory map and details of upgrades or modifi­cations recommended by the respective manufacturers. The final chapter is about servicing the IBM and compatible PCs. It starts with a brief description of the original IBM XT and works through to the PS/2 80. While the chapter mainly covers IBM machines, the Amstrad PC1640 block diagram and other details are included. Details and pin connections of the 8087 maths co-processor, the 8273A DMA (Direct Memory Access) controller and the 8253 (PIT) programmable interval timer, as well as several other im­portant chips, are given, along with a Qbasic program to test whether a co-processor is fitted to the PC board. The memory terminology for PCs is explained as well as the function of the CMOS RAM and the BIOS (Basic Input Output System) ROM. The chapter continues with a description of the evolution of the PC bus and concludes with details of the video modes and colours available with each mode. A reference section of some 40 pages concludes this book, containing information on commonly used symbols, RAM data, char­acter sets, power on self test and seven other useful summaries. To conclude, a very interesting book which covers all as­pects of PCs, from basics to quite advanced fault finding. Our copy came from Butterworth-Heinemann Australia, PO Box 5577, West Chatswood, NSW 2067. Copies can be obtained from SILICON CHIP. The ordering details are shown in the SILICON CHIP Bookshop advertisement in this issue. SC September 1995  89