The ad to the left is from the August 1978 issue of Music Life Magazine (published in Japan). The ad states the Yamaki FM Sound Locator to be an “Electric Revolution,” allowing “A guitar sound from the radio!!”

The ad shows two components to the system - a FM Transmitter for ¥6,700 and a FM Sound Locator for ¥17,000. Combined you have a wireless system for your guitar. Either play through a radio (tuned to 77~90MHz) or a guitar amp using the Sound Locator.

At the bottom of the ad Daion is listed as the distributor.

The pictures in the gallery below show a lot more detail than what we can see in the small black and white image from 1977. On the box you can clearly see Daion Co. Ltd. as the distributor.

The unit need 9 volts and can be powered either by a battery via a door on the bottom, or a 9v adaptor on the back. There is a thumb wheel on the right of the front cover that allows you to pick the frequency to match your FM receiver. The antenna raises to an impressive 28”, and when compressed, it stores using a plastic clip on the top of the unit.

There is a switch on the front left to toggle between 9v battery, off, or 9v DC power. The little window above the switch has a battery and tuning meter. There is a 1/4” phono jack on the back to plug in your guitar.

Amazingly, the original packaging has survived and we get to see what this item might look like fresh “out of the box.” The FM-170L metal case is approximately 6” wide by 3” deep by 2.25” tall, so it’s not a very large item.