Aiwa HS-J303 and HS-J900 Service Manual

The HS-J303 and HS-J900 were stereo radio cassette recorders manufactured in 1989 by the Aiwa Corporation of Japan. These models were essentially identical except for differences in the tuning range of the AM band. They required two AAA size batteries, and could also accept power through the DC socket. The audio power output was 10 mW (EIAJ/16-Ω) per channel.

Review

When you look at the circuit diagram in this service manual, you will see a staggering number of SMD components including integrated circuits (ICs), and consequently the main board is densely populated. In terms of electronic engineering, the design was one of the most advanced; however the outside case was plastic in plain black making it look average.

In this design, they used a microcontroller IC TC9308AF-014, which also drives the liquid crystal display (LCD). In the tuner section the FM front end is TA8158F, whilst the IF MPX functions are provided by the TA8132AF. For the tape recorder circuitry they used the CXA1278N which provides the head preamplifier and record amplifier functions. The Dolby noise reduction is provided by separate IC BA1102FS, and the headphone power amplifier by yet another separate IC TA7688FS. Finally the motor control IC is AN6612S. In order to power all these ICs, and provide the necessary voltage rails, they use a dc-dc converter IC TA8126F. There is also a plethora of discrete component circuits providing logic control, and voltage regulation. The sound quality is extremely good providing you use a good pair of headphones.

Price/eBay

The HS-J303 and HS-J900 portable stereo tape recorders are often for sale on eBay and the prices can vary drastically according to their condition. These units come in a plane plastic case construction and therefore when damaged or scratched, their value drops considerably. A unit in mint condition with the original box, packaging, and accessories, can sell for well over one hundred pounds. However, a broken unit that is scratched and damaged for less than half that. These units are extremely time-consuming to repair and calibrate and therefore service costs are high.

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