Ultra-rare 1968 SANSUI TU-777, as-is, Sansui, power confirmed

1968 Sansui TU-777
Original circuit diagram included

This is believed to be a very rare model.

The circuit diagram is enclosed in an envelope found on the bottom.
This will be included.

Please judge from the images.
We are looking for buyers who understand that this is a currently sold item with unconfirmed operation.

Returns and exchanges are not possible.
Please understand.

Below is from reference material.

An FM/AM tuner equipped with various functions as a top-class tuner, including a front end with FET and a 4-gang variable capacitor for RF2 stages, 3-stage AGC, 5-stage IF, and 4-stage limiter.

The FM front end uses a junction FET for the first RF stage, and silicon transistors and a 4-gang variable capacitor for the second RF stage, mixer, and oscillator circuits.

The 5-stage IF with silicon transistors and the 4-stage limiter boast high amplification, high stability, low noise, and low distortion.

With a 3-stage AGC, including two stages in the front end and one non-tuned stage specifically for AGC in the IF section, selectivity is ensured even in strong electric fields.
The power supply for the IF stage and front end uses a Zener diode stabilized power supply. In particular, the front end completely temperature-compensates the local oscillator, and further stabilizes the power supply to minimize local oscillator drift, successfully eliminating the need for an AFC circuit.

The noise canceller adopts a new method that can remove noise without cutting off the high-frequency audible range, instead of the conventional high-cut method. Combined with the 4-stage limiter, it provides comfortable, noise-free reception.

Dedicated amplifiers for the meter and muting are provided, and a large meter with a green ring circular dial is used for tuning indication, making it easy to see and allowing for sharp tuning to the center of the radio wave.

The multi-circuit has been siliconized and adopts the most stable and reliable switching method to improve channel separation.
It is equipped with a purely electronic FM stereo/monaural switching system.

In FM-AUTO mode, the electronic switch automatically operates when an FM broadcast switches from monaural to stereo.
The FM antenna is equipped with a 20dB down attenuator with a local/distant switch, so it will not distort even if the input to the antenna is up to about 3V.