TPM-8050 My First Sony Cassette Player
The TPM-8050 was a mono cassette player manufactured by the Sony Corporation and assembled in Thailand. It was a part of the "my first Sony" range of audio consumer electronics that Sony targeted for children. It was a very basic player power by a pair of C size dry cells, with rewind/review tape function, and three preset volume settings of high, middle, and low. The tape transport mechanism was very basic with plastic cogwheels, and one drive belt. This is a nice little player for the office desk. Its dimensions are 166 mm × 27 mm × 197 mm, and mass 420 g not including batteries.
Review
This cassette player had a strange design, where the play and stop buttons were electrical switches. The three preset volume settings were also switches, which were part of an elaborate discrete transistor circuit. It occurred to me that surely a simple rotary volume control would have been cheaper and better to use, then a handful of transistors and switches.
The electronic circuit uses the AN7118 integrated circuit (IC), which is a power amplifier, to drive the built-in loudspeaker. There is also the BA6227 servo control IC which drives the DC motor (RF-300C-14270). Interestingly, the playback head preamplifier is a discrete component stage consisting of 2SC1740S transistors.
Price/eBay
These units are becoming scarce every year, and I would imagine not many would have survived from the 1990s. It was an iconic design that many would remember and want to have to relive their youth. A good working unit in mint condition and in its original box could fetch around fifty pounds on a good day and possibly more. One needing repairs may bring around ten pounds.
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TPM-8050 My First Sony Cassette PlayerElectronic Engineering
Chipset
Repair
Drive Belt
Loudspeaker
Power Supply