pss-140: The Interfacing
The PSS-140 is a small FM-synthesis based keyboard from the late 1980's, its sound chip is the YM2420, this chip is almost identical to the YM2413, the only obvious difference being a slight change in register layout. The built in functionality does not do justice to the capabilities of the sound chip. I therefore installed a DB-25 way connector into the keyboard such that the sound chip may be controlled via the parallel port.

At the splice point tri-state buffers where installed such that the original operation of the keyboard is still possible. The toggle switch on the rear selects mode of operation. A volume control was also added to the keyboard to reduce the output level to prevent clipping.



YM2420 Vgm Player