Silicon ChipMarket Centre - August 1992 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: The Pay TV farce: where to from here?
  4. Vintage Radio: Troubleshooting vintage radio receivers by John Hill
  5. Feature: The Musical Instrument Digital Interface by Michael Hawkins
  6. Project: Build An Automatic SLA Battery Charger by Darren Yates
  7. Project: Miniature 1.5V To 9V DC Converter by Darren Yates
  8. Feature: Amateur Radio by Garry Cratt, VK2YBX
  9. Serviceman's Log: How I ended up in the sync by The TV Serviceman
  10. Feature: Remote Control by Bob Young
  11. Project: Dummy Load Box For Large Audio Amplifiers by Leo Simpson
  12. Project: The Interphone Digital Telephone Exchange; Pt.1 by Jeff Monegal
  13. Feature: The Story Of Electrical Energy; Pt.19 by Bryan Maher
  14. Back Issues
  15. Order Form
  16. Market Centre
  17. Advertising Index
  18. Outer Back Cover

This is only a preview of the August 1992 issue of Silicon Chip.

You can view 49 of the 96 pages in the full issue, including the advertisments.

For full access, purchase the issue for $10.00 or subscribe for access to the latest issues.

Items relevant to "Build An Automatic SLA Battery Charger":
  • Silicon Chip article scan, August 1992 - 6/12V SLA Battery Charger (AUD $10.00)
Articles in this series:
  • Amateur Radio (November 1987)
  • Amateur Radio (December 1987)
  • Amateur Radio (February 1988)
  • Amateur Radio (March 1988)
  • Amateur Radio (April 1988)
  • Amateur Radio (May 1988)
  • Amateur Radio (June 1988)
  • Amateur Radio (July 1988)
  • Amateur Radio (August 1988)
  • Amateur Radio (September 1988)
  • Amateur Radio (October 1988)
  • Amateur Radio (November 1988)
  • Amateur Radio (December 1988)
  • Amateur Radio (January 1989)
  • Amateur Radio (April 1989)
  • Amateur Radio (May 1989)
  • Amateur Radio (June 1989)
  • Amateur Radio (July 1989)
  • Amateur Radio (August 1989)
  • Amateur Radio (September 1989)
  • Amateur Radio (October 1989)
  • Amateur Radio (November 1989)
  • Amateur Radio (December 1989)
  • Amateur Radio (February 1990)
  • Amateur Radio (March 1990)
  • Amateur Radio (April 1990)
  • Amateur Radio (May 1990)
  • Amateur Radio (June 1990)
  • Amateur Radio (July 1990)
  • The "Tube" vs. The Microchip (August 1990)
  • Amateur Radio (September 1990)
  • Amateur Radio (October 1990)
  • Amateur Radio (November 1990)
  • Amateur Radio (December 1990)
  • Amateur Radio (January 1991)
  • Amateur Radio (February 1991)
  • Amateur Radio (March 1991)
  • Amateur Radio (April 1991)
  • Amateur Radio (May 1991)
  • Amateur Radio (June 1991)
  • Amateur Radio (July 1991)
  • Amateur Radio (August 1991)
  • Amateur Radio (September 1991)
  • Amateur Radio (October 1991)
  • Amateur Radio (November 1991)
  • Amateur Radio (January 1992)
  • Amateur Radio (February 1992)
  • Amateur Radio (March 1992)
  • Amateur Radio (July 1992)
  • Amateur Radio (August 1992)
  • Amateur Radio (September 1992)
  • Amateur Radio (October 1992)
  • Amateur Radio (November 1992)
  • Amateur Radio (January 1993)
  • Amateur Radio (March 1993)
  • Amateur Radio (May 1993)
  • Amateur Radio (June 1993)
  • Amateur Radio (July 1993)
  • Amateur Radio (August 1993)
  • Amateur Radio (September 1993)
  • Amateur Radio (October 1993)
  • Amateur Radio (December 1993)
  • Amateur Radio (February 1994)
  • Amateur Radio (March 1994)
  • Amateur Radio (May 1994)
  • Amateur Radio (June 1994)
  • Amateur Radio (September 1994)
  • Amateur Radio (December 1994)
  • Amateur Radio (January 1995)
  • CB Radio Can Now Transmit Data (March 2001)
  • What's On Offer In "Walkie Talkies" (March 2001)
  • Stressless Wireless (October 2004)
  • “Degen” Synthesised HF Communications Receiver (January 2007)
  • WiNRADiO: Marrying A Radio Receiver To A PC (January 2007)
  • PICAXE-08M 433MHz Data Transceiver (October 2008)
  • Half-Duplex With HopeRF’s HM-TR UHF Transceivers (April 2009)
  • Dorji 433MHz Wireless Data Modules (January 2012)
Articles in this series:
  • Remote Control (August 1992)
  • Remote Control (September 1992)
  • Remote Control (October 1992)
Items relevant to "Dummy Load Box For Large Audio Amplifiers":
  • Silicon Chip article scan, August 1992 - Dummy Load Box For Large Audio Amplifiers (AUD $10.00)
Articles in this series:
  • The Technology Letters, Pt.2 (January 1989)
  • The Story Of Electrical Energy (July 1990)
  • The Story Of Electrical Energy; Pt.2 (August 1990)
  • The Story Of Electrical Energy; Pt.3 (September 1990)
  • The Story Of Electrical Energy; Pt.4 (October 1990)
  • The Story Of Electrical Energy; Pt.5 (November 1990)
  • The Story Of Electrical Energy; Pt.6 (December 1990)
  • The Story Of Electrical Energy; Pt.7 (January 1991)
  • The Story Of Electrical Energy; Pt.8 (February 1991)
  • The Story Of Electrical Energy; Pt.9 (March 1991)
  • The Story Of Electrical Energy; Pt.10 (May 1991)
  • The Story Of Electrical Energy; Pt.11 (July 1991)
  • The Story Of Electrical Energy; Pt.12 (August 1991)
  • The Story Of Electrical Energy; Pt.13 (September 1991)
  • The Story Of Electrical Energy; Pt.14 (October 1991)
  • The Story Of Electrical Energy; Pt.15 (November 1991)
  • The Story Of Electrical Energy; Pt.16 (December 1991)
  • The Story Of Electrical Energy; Pt.17 (January 1992)
  • The Story Of Electrical Energy; Pt.18 (March 1992)
  • The Story Of Electrical Energy; Pt.19 (August 1992)
  • The Story of Electrical Energy; Pt.20 (September 1992)
  • The Story Of Electrical Energy; Pt.21 (November 1992)
  • The Story Of Electrical Energy; Pt.22 (January 1993)
  • The Story of Electrical Energy (April 1993)
  • The Story Of Electrical Energy; Pt.24 (May 1993)
  • The Story Of Electrical Energy; Pt.24 (June 1993)
...__TCENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. r-------------------------, CLASSIFIED ADVERTISING RATES : Advertising rates for this page: Classified ads: $10.00 for up to 15 words plus 40 cents for each additional word. Display ads (casual rate): $20 per column centimetre (Max. 10cm). Closing date: five weeks prior to month of sale. I I To run your classified ad, print it clearly on the form below or on a separate sheet of paper & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02) I I I I m~. I I I I I I I I ANTIQUE RADIO ANTIQUE RADIO restorations. Your one-stop radio repair shop. Specialising in restoring vintage radios, including chassis rewiring, re-condensing, quality new parts, valves, valve sockets, speakers, power & audio transformers. Second hand radio dials & parts for most brands & models. About 400 radios in stock for sale, restoration & parts. Every restored wireless is covered by a 2year warranty on parts & labour. We restore damaged woodwork & cabinets & French polish (approx. 40 coats). Vintage car radios available for sale or restoration. Repairs done on tape decks. Open Sat. 10am-5pm; Sun. 12.30-Spm. 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or (02) 726 1613 AH. FOR SALE Enclosed is my cheque/money order for $_ _ _ _ or please debit my o Bankcard O Visa Card O Master Card Card No. Signature,_ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _-'/_ __ Name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Street _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Suburb/town _ _ _ _ _ _ _ _ _ _ _ _ Postcode_ _ _ _ __ XI I I I I I I I I I L-------------------------J 94 SILICON CHIP WEATHER FAX programs for IBM XT/ ATs *** "RADFAX2" $35 is a high resolution, shortwave fax, Morse & RTTY receiving program. Suitable for CGA, EGA, VGA and Hercules cards (state which). Needs SSB HF radio & Radfax decoder. *** "SATFAX" $45 is a NOAA, Meteor & GMS weather satellite picture receiving program. Needs EGA or VGA plus "WEATHER FAX" PC card . *** "MAXISAT" $75 is similar to SATFAX but needs 2Mb expanded memory (EMS 3.6 or 4.0) and 1024 x 768 SVGA card. All programs are on 5.25-inch or 3.5-inch disks (state which) & include documentation. Add $3 postage. Only from M. Delahunty, 42 Villiers St, New Farm, Old 4005. Phone (07) 358 2785. 8051 MICRO-COMPUTER PROTOTYPING PCB $30 - similar to my ROMLoader EA Jan 92. Provision for 8255 PPI, 9346 EEPROM, 2k-32k SRAM, 2k- 32k EPROM, MAX232, DIP switches & expansion header. Send A4 SAE for article. Tantau, PO Box 206, Gordon 2072. A 4Mb SIMM can now be used in my Printer Buffer kit, and my PC printer MEMORY EXPANSION PRICES AT JULY 1ST, 1992 SIMM 1Mbx9 80ns 1Mbx8 100ns 1Mbx8 80ns 4Mbx9 80ns 4Mbx8 80ns 256x9 80ns (FOR SIP ADD $1) TOSHIBA T1000SE 2Mb T2000SX 4Mb T1600 2Mb T31 000SX 2Mb T3200SX 2Mb T3200 3Mb T5200 2Mb T2000SX 8Mb T44/6400 4Mb $48 $42 $45 $180 $160 $16 $155 $275 $140 $135 $135 $230 $150 $525 $330 DRAM-DIP 41100080 256 X 4 80 4125680 1Mbx4 80Z 1Mb x 4 80S $540 $5.60 $2.00 $24.00 $24.00 DRIVES 3½ PANAS 1.44 $78 S'GATE IDE 64/16 $365 S'GATE IDE 42/28 $325 S'GATE IDE 108/16$475 S'GATE IDE 130/16$530 CO-PROCESSORS 387/33/40 $235/$280 387/20/25 $210/$215 sx 20/25 $155/$170 287/10/20 $95/$100 Safes Tax 20%. Overnight Delivery. Credit Cards Welcome. PELHAM Tel (02) 980 6988 Fax (02) 980 699 r Plans Kits and PCBs UNIDEN SCANNERS DON'T PAY MORE! 100W Valve Amp PCB ............................................... $30 Valve Amp PSU PCB ................................................. $25 Universal PSU (±5/±12V) Dual Supply ...................... $10 Digi 125 100W amp/pair........... .. .......... $10 ETI 1623 PIA for PCs ............................................ $40 Max 1/0 Board ............................................................ $40 Max Kit ............................................. $169 LM380 3.5 amp PCB .................................. .. ............. $7 AEM 35W amp kit .......... ......................... . $20 ETI Audio Toolkit PCB...... ... $10 AGC Amp PCB .................. ...................... $7 Z-80 Miniprocessor PCB... .. ....................... $50 6502 Miniprocessor PCB ........... .. ........ $50 6809 Miniprocessor PCB .................. $50 8048/8049 Developers board complete B& T .. ,........ $199 IBM PC Prototype PCB .............................................. $50 EPROM Programmer ........................... $299 ESL-1 Electrostatic speaker kiVpair inc manual ...... $899 ESL-1 Assembly Manual ...................................... ... $50 50XL RRP $299.95. Our price $211 10 memories, Lo-Hi VHF, UHF 1 OOXL T RRP $449.95. Our price $409 100 memories, Lo-Hi VHF, Air, UHF 200XLT RRP $549.95. Our Price $477 200 memories , Lo-Hi VHF, Air, UHF, 800 MHz CB, SCANNERS MARINE For more information, write to: TopCom Communications, Reply Paid 336 (no stamp) PO Box 336, Greensborough 3088. \.. Phone (03) 883 9535. Fax (03) 432 0716. ~ FIX-A-KIT KIT REPAIR & CONSTRUCTION TRANSFORMER REWINDS ALL TYPES OF TRANSFORMER REWINDS TRANSFORMER REWINDS ~eply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph: (065) 761291. Fax: (065) 761003. port driven ZB0 Micro Development board has a Basic Interpreter. Short form kit prices include postage. Buffer $52, ZB0 Dev. $76. For more information, send a 45c stamp to Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. Phone (03) 338 6286. SWITCHED MODE POWER SUPPLIES: compact enclosed ex-Telecom supplies. Dimensions 300 x 90 x 180mm. Unregulated input 30-50V, regulated output of 12V<at> 6A or 12V<at> BA or 5V <at> 40A. Three different units. Limited stocks <at> $28 ea. P+P $7 (heavy!). Specify type when ordering (item No. 0145). * MUSIC ON HOLD PCB: small PCB assembly based on a 7910 CF music generator IC. Apply 312V across two of connector pins to obtain music from one of the IC pins. Basic information and a circuit diagram 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION , " TECHNICAL ASSISTANCE HVCAL ELECTRONICS Design, Manufacture & Repair of Electronic Equipment (02) 633 5477 P.C. Computers (08) 332 6513 36 Regent St, Kensington SA. KIT REPAIRS Kits repaired from all magazines. Switchmode power supplies repaired. Design work from start to finish. Computer software consultancy. Ring any time 9am-9pm Mon-Sun EEM ELECTRONICS is provided. $4 ea (item No. 0146). * MICROSWITCH COLLECTION: a mixture of no less than 10 small and large, new, mil-spec microswitches. $6 for the collection (item No. 0148). * MAINS RATED RELAYS: four separate SPST switches (24A) actuated by a mainsrated solenoid. $10 ea (item No. 0128). We also have some SPOT mains relays which will switch up to 10A AC. These are fully enclosed in an attractive clear plastic housing. $12 ea (item No. 0149). * LARGE ROTARY SWITCHES: these large rotary switches have- "snap in" action and all are rated at mains voltages or higher. They have at least three positions and have currents ratings from 10-35A. Great for high power mains and antenna switching. Only $15 ea (item No. 0151 ). * LARGE FANS: powerful ball bearing mains powered fans, 220V/0.13A, WANTED: YOUR CIRCUIT & DESIGN IDEAS Do you have a good idea languishing in the ol' brain cells. If so, why not sketch it out, write a brief description of. its operation & send it to us. Provided your idea is workable & original, we'll publish it in Circuit Notebook & you'll make some money. We'll pay up to $60 for a really good circuit but don't make them too big please. So transfer your idea to paper & send it to Silicon Chip Publications, PO Box 139, Collaroy Beach, NSW 2097. 10 Bouverie Place, Epping, Vic 3076 Phone (03) 401 1393 WANTED DISTORTION TEST SETwanted. Must be auto-nulling and in good condition with the instruction manuals. Can be Audio Precision, Sound Technology 170x, Hewlett Packard 339 or equivalent standard. If you have one to sell, please contact Leo Simpson on (02) 979 5644 with details and price. 173mm diameter by 60mm deep. Thermally protected, finger guard included, removed from new equipment. $9.90 (item No. 0152). * TEMPERATURE CONTROLLERS: mechanical temperature switches, designed for switching air conditioning (heating/cooling) systems directly. Adjustable temperature controls and mains-rated switches, can control currents of at least BA directly. Most are rated for typical ambient ranges but some higher temperature types are also available. All come with specifications. $35 ea (item No. 0152). * PRESSURE AND TEMPERATURE GAUGES: brand new, large mil-spec gauges. Overall diameter approx AUGUST 1992 95 r-------------------------, SILICON CHIP BINDERS l These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers and are made from a distinctive 2tone green vinyl that will look great on your bookshelf. Advertising Index Adi lam Electronics ...... ......... .. OBC Altronics ... ........ ..... ..... .... ...... . 10-13 All Electronic Components .. ...... 59 Antique Radio Restorations ....... 94 A-One Electronics ................ 34,35 Av-Comm .............. .. .. ....... .. .. ...... 33 * High quality. AWA Distribution ...................... IBC * Hold up to 14 issues Breakthrough Computers ........... . 9 Comma Corporation ..... .. ............. 4 * 80mm internal width. * SILICON CHIP logo printed in gold- David Reid Electronics .. .............. 3 EEM Electronics ............. ...... ..... 95 coloured lettering on spine & cover. Electronic World .......... .. ........... ... 4 Emona Instruments ................... 55 Yes! Please send me _ _ _ SILICON CHIP binder(s) at $A11.95 plus $A3 p&p each (NZ $A6 p&p). Enclosed is my cheque/money order for $_ _ _ _ or please debit my o Bankcard D Visa Card D Master Card Geoff Wood Electronics ............. 67 Harbuch Electronics .................. 43 Hewlett Packard ... ... ..... ... .. ........ 25 Hycal Instruments ............. ......... 95 lcom Australia .... ...................... IFC Jaycar Electronics ...... .... ... ... 45-52 Card No. J.V. Tuners .......... ... .. ... ............... 43 Name _ __ _ _ _ __ _ _ _ __ _ _ _ _ _ _ _ __ _ Kenwood Electronics .... ...... .. ..... 74 KT Technology ... .............. .. ........ 65 Oatley Electronics ................ 61,95 Street _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ __ Pelham ............................ .... . 73,95 Suburb/town _ _ _ _ _ _ _ _ _ _ _ Postcode_ _ _ _ __ Peter C. Lacey Services .. .. ........ 40 Philips Test & Measurement ...... 31 Signature_ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _~/_ __ PC Computers ....................... .... 95 SILICON CHIP PUBLICATIONS PO Box 139, Collaroy Beach, NSW 2097, Australia. Phone (02) 979 5644 Fax: (02) 979 6503. L-------------------------J RCS Radio ..... .. ......................... 96 Reserve Electronics .................... 4 Resurrection Radio ..... ... ... .. ...... ... 7 Rod Irving Electronics .......... 76-81 Silicon Chip Binders ............. 60,96 TECS Electronics & Computers. 37 130mm. Pressure gauge reads from 016 bar, temperature gauge reads from 20-80°C and has a remote sensor attached to a 2-metre lead. Pressure gauge $32 (item No. 0153A) . Temperature gauge $29 (item No. 0153B). * MAINS SWITCHES: large 3-pole 20A/ 500V switches as used to switch machinery $18 ea.* UHF REMOTE CONTROL BARGAIN: one single channel receiver PCB and all on-board components kit as per EA April 1989 and two complete transmitter kits (include cases and the battery). Yes, one receiver and two transmitters for an incredible total price of $39.90. Two months only, at this special Market Centre bargain searcher's price. Major cards accepted with phone and fax orders. Certified p&pAustralia $5, NZ (airmail $10. Oatley 96 SILICON CHIP Electronics, PO Box 89, Oatley, 2223 NSW. Phone (02) 579 49485. Fax (02) 570 7910. Telecom Australia ...................... 57 Transformer Rewinds ................ 95 TopCom Communications ......... 95 PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd is the only company that manufactures and sells every PC board and front panel published in SILICON CHIP, ETI and EA. ACS Radio Pty Ltd, 651 Forest Rd, Bexley 2207. Phone (02) 587 3491 • Jemal Products, 5 Forge St, Welshpool, WA 6106. Phone (09) 350 5555. • Marday Services, PO Box 19-189, Avondale, Auckland, NZ. Phone 88 5730. • RCS Radio Pty Ltd, 651 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491.