Sony’s boombox series from the 80ies with a special technology for bass improvement had the strange name “DoDeCaHorn” and is probably not well known outside of Japan. The top of the line models were CFD-700 and CFD-900. The 700 has a 5-band equalizer with mechanical sliders and a mechanical switch to change the functions to Tape, Radio, CD, AUX, that could not be operated with remote control. On the 900 all is electronically controlled and can be operated with RC. I started with the CFD-700 that is often available on Japan’s Yahoo auctions. I could repair it as good as possible. After that I was thinking, that I need the more sophisticated CFD-900. At the end I had to order two devices to make one almost fully working. Those boomboxes are fully crowded with electronics and have a lot of IC’s inside. If there is something wrong, it will be difficult to repair. But luckily most problems are just related to mechanics, especially on the tape decks. So I found out, that Sony here used some kind of grease that hardened over the time. The tape mechanism then was not movable anymore. I cleaned it with iso and used some oil to loosen everything. The tape mechanisms are not easy accessible, as on the back side is attached the pre-amp board with a lot of wires. I made a lot of pictures to bring it back to initial state. Of course also all 4 belts had to be replaced. During my work on this device I added some additional features: As the radio has only the Japanese FM frequency range from 76…90MHz, I built in an FM converter that shifts frequency for 10MHz and 20MHz. Now I can listen to German FM radio. The display is illuminated with incandescent bulbs and lights up only when attached to AC Mains. As on one display some bulbs were burned, I changed it to orange LED’s and connected them to another point on PCB, so that they work now also in battery mode. Furthermore I added LED’s to tape decks and the CD-Player. On CD player it is possible to change the color as there are RGB LED’s. On the next pictures are some impressions of the repair process. Some bulbs are burned Pre-amp board on back side of tape decks Tape decks during adding LED's New LED's, painted the board with white color to make it brighter FM Converter RGB LED stripe in CD-Player Controller for RGB LED's The final result Here a comparison of Display with bulbs (front) and display with LED’s (back). Small video, showing the functions after repair:
Great work, that's an amazing box. I love how little LEDs can really enhance some of the features and the cassette deck wells look super-cool back-lit. Your not kidding about it packed with electronics but it looks like a very modular design with lots of connectors. How much do they weigh?
Nice Job !!! Wish I can also upgrade the lights on my CFD-DW97. The DW97 is the TOTL older version of the DaDecaHorn series with more discrete parts than IC's. Also, luckily it has full FM bandwidth to 108Hz. The upgrade I did is just change the flimsy 7 watts fullrange speakers to a Sharp 15 watts fullrange with same diameter and the sound became awesome ! I noticed the newer CFD-900 and 700 has a new full range speaker design. Is it beefier ? How many watts ? How's the sound ?
I cannot compare to Panasonics RX-DT9, as I don't have one. But compared to AIWA's Strasser CSD-SR8 it delivers a similar warm sound with good bass. But as the bass with the woofer is directed to the back side it depends on the placement, how strong the bass will be. If closer to a wall, it is stronger. The full-range speakers with their special design are made of Carbon and Titanium. The nominal power is also only 7W. You wrote, that you replaced your speakers with Sharp 15 watts fullrange. Which exact type did you use?
Hi...Got an Aiwa unit of comparable capacity, made around 1988, it actually is being used every day, however unfortunately the LCD shows have begun to obscure from age, the CD player requires one more KSS210 laser get together, and keeping in mind that it is just 11 beats on eBay, I really have not tuned in to a CD in years. Cassette player ( the extravagant double deck with fast naming) the equivalent, all the elastic parts and a decent number of plastic pieces are broken, so it is a pleasant FM radio now, with an underlying clock and the capacity to have coordinated turn on. smt assembly services
