Aiwa HS-JX707 Service Manual

The HS-JX707 and HS-JX707D were AM/FM stereo radio cassette recorders manufactured in 1992 (approx.) by the AIWA Corporation of Japan. Both models were virtually identical except that the JX-707D had additional TV reception capability (175 MHz to 222.5 MHz) and therefore different tuner PCB. For the power source, these units could operate on two AAA size dry cells or a rechargeable battery PB-S5. The mains battery charger varied depending upon the country, and there is more information about this in this service manual. The maximum audio power output is 10 mW per channel (EIAJ/16 Ω). The dimensions are 76.2 mm × 107 mm × 27.2 mm, and mass 220 g including rechargeable battery.

Review

At this point in the history of portable stereo cassette players, we see a bold design that is capable of recording on both sides of the cassette through the auto-reverse function, and an elaborate radio tuner capable of receiving analogue TV sound. In addition it also boasts built-in timer and alarm/sleep functions, and voice navigation! The electronic engineering is extremely complex with high component count and board density.

The TV/FM front end functions are provided by TA8152AFN, whilst the AM/FM detection, IF, and MPX by TA8132AF. The main microcontroller, which also drives the LCD, is TC9316F-003. It also interfaces with the MSM6374-534GS voice navigation IC.

For the audio functions, they use the XRC5484 microcontroller. The heads connect to the preamplifier/record amplifier IC TA8155FN. For the Dolby noise reduction function they use a pair (one for each channel) of NJM2065 integrated circuits, and the headphone driver IC is TA7688F. Interestingly, this design uses a 3-phase disc motor driven by TPIC326ADB, and consequently the speed is extremely smooth. Just when you thought that one cannot possibly fit all of these ICs in such a small space, they also fitted a mecha-com IC TB2003-003FN. In addition there is a plethora of discrete transistor circuits, and dc-dc converter ICs to establish all the necessary voltage rails from just 3 V.

This design demonstrates an extreme level of engineering complexity, and when they are new and fully working, the sound quality, and operation are a joy to experience. Never again will this level of engineering brilliance be seen in modern manufacturing today.

Price/eBay

These portable cassette recorders occasionally come up for sale and it is rare to find a unit in mint condition together with its original accessories and packaging. Such a unit in good working condition would be worth in the hundreds. This is a very complex construction and changing the drive belt is very time-consuming and expensive.

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