【Overview】 ・This item is a repair and restoration of a junk item from approximately 50 years ago. Although the normal operation of all functions has been repeatedly confirmed, it is being sold as a junk item due to its age. Due to the recent increase in return scams, we are very reluctantly unable to accept returns. Except for complete non-functionality, please understand that this item is sold as-is, with no claims or returns. As an exception, we will provide free repair if you cover the round-trip shipping costs. 【Product Description】 Product: Stereo Cassette Deck Manufacturer: Sony Model Number: TC-K4 Release Date: 1976 Price: 59,800 yen 【Appearance】 ・The front panel is almost free of scratches and is clean, but there is a very slight rust-like appearance on the body. However, considering its age, I believe it is in good condition. 【Repairs and Adjustments】 ・Complete disassembly and cleaning of the front and rear drive sections, and grease application ・Complete disassembly and cleaning of the head block, and repair ・Volume controls for recording and playback, ultrasonic cleaning with ethanol ・Record/playback switch, complete disassembly and ultrasonic cleaning with ethanol ・Capstan, auto shut-off, and counter belt replacement ・Auto shut-off and cassette loading mechanism repair ・First-stage amplification circuit, mid-stage amplification circuit, and Dolby circuit repair ・Headphone circuit and AC bias signal circuit repair ・Electronic control motor speed adjustment ・Playback, recording, VU meter sensitivity, and head azimuth adjustment ・Cleaning of the record/playback head, pinch roller, and capstan 【Operational Check】 ・All functions have been confirmed to work, including recording, playback, pause, fast forward, rewind, and timer standby. 【Sound Quality Check】 ・Based on listening tests with commercially available music tapes, I believe the sound is sufficient for enjoying music as a cassette deck from approximately 50 years ago (wow and flutter 0.12%, which is excellent). (Recording and playback may be poor depending on the condition of the tape) 【Included Accessories】 ・One test tape used for recording, playback, and adjustment 【Important Notes】 ・Please use the device for only 1-2 hours a day, as the resin parts have deteriorated over time and may cause malfunctions. ・The playback speed (pitch) can be finely adjusted with the semi-fixed resistor in the servo motor circuit, although it requires opening the chassis.