Refurbished Technics RS-M255X Stereo Cassette Deck

This is the Technics RS-M255X cassette deck, which was popular in the early 1980s.
It wouldn't be an exaggeration to say that this machine played a key role in popularizing dbx noise reduction in Japan.

★ Condition
There are a few small scratches on the face panel, but none are noticeable, and overall I would say it's in excellent condition.
The face panel, control buttons, and knobs have all been disassembled, and each one has been cleaned and polished.
The level meter's display window, which is prone to dirt accumulation due to static electricity, has been polished on both sides, making it clear and vibrant.
When it comes to audio equipment, sound quality is important, but appearance is just as important.

★ Operation & Maintenance Details
I opened the top cover and removed the cassette mechanism, then proceeded to disassemble it step by step. The internal wiring was neatly bundled with cable ties from the time of manufacture, indicating that it had not been disassembled by an amateur before.

I disassembled the cassette mechanism and replaced all three belts with new ones. From left to right in image 6 are the mode belt, reel belt, and capstan belt. Technics belts are great because even when they get old, they only stretch and don't melt into a gooey mess due to hydrolysis like other manufacturers' belts.

The motor belt has been upgraded from the standard 1.4mm square to 1.6mm square. This is my original modification, which I always do when maintaining this mechanism, because the motor-side pulley diameter is small and the 1.4mm square belt is prone to slipping. I have applied this modification to more than 10 units so far, and not a single instance of slipping has occurred.
The mode belt passes through a narrow gap between the cassette mechanism and solenoid, and because the top and bottom of the pulley shaft are closed, it's impossible to replace the belt in its original loop form using conventional methods. I've previously acquired some used items where the belt had been cut and the joint glued, but of course, I wouldn't do such a shoddy job. I always replace it in its original loop form.

Next, we inspect the resin cap on the idler shaft, which is another weak point of this mechanism. If this cap cracks due to age-related deterioration, the spring force will push it out and cause it to come into contact with the frame, preventing the idler arm from swiveling from side to side, making fast forward and rewind impossible. The inspection revealed that the cap was in good condition and there were no cracks. (Image 7)

When replacing the belt, spindle oil was applied to the motor shaft and all rotating parts. (Image 8)
The pinch roller and idler were in good condition and were cleaned with a special cleaner before being reused.
In addition to cleaning, the head was also demagnetized. This alone improves the extension of the high frequencies.

After the maintenance was completed, the cassette mechanism was returned to the main unit and confirmed to be working correctly. The head moves up and down smoothly in response to the operation buttons. After playing it for about an hour to allow the parts to settle in, the tape speed was adjusted to the standard value using a test tape with a 315Hz reference signal recorded on it. In cassette decks and boomboxes, the tape speed changes when the capstan belt is replaced, so the correct tape speed cannot be achieved without adjusting it in this way. Doing it by guesswork is out of the question. (Image 9)

Finally, when I connected it to an amplifier and played some music, it sounded quite good. Audio equipment from that era uses much better components than modern products that have been drastically reduced in cost.
Recording works fine. I tested it with noise reduction off, Dolby on, and dbx on. When comparing the sound, the effect of dbx is truly remarkable. With Dolby, there's a faint tape noise, but when recording with dbx, the music starts instantly from complete silence, just like a CD or data audio. It's hard to believe this is a cassette deck from over 40 years ago.
Maintenance is now complete.

This listing is for the deck unit only; no accessories are included.
*The tape shown in the picture is for photographic purposes only.