Yamaha YM2612
About this component
The YM2612 produces the FM music, under control of the Z80. Channel 6 can be switched to play 8-bit PCM samples streamed by the CPU. Its 9-bit DAC causes the well-known 'ladder effect' distortion at low volumes, which the later YM3438-based ASICs largely fix. Muffled or distorted audio on VA7 and early Model 2 consoles is usually caused by the op-amp audio circuit rather than the sound chip. Part variants: Discrete YM2612 on Model 1 VA0–VA6.8 and Model 2 VA2/VA2.3 (Toshiba ASIC boards). VA7 Model 1 and most Model 2 boards use a modified YM3438 core inside the FC1004-family ASIC (315-5487 / 315-5660 / 315-5700); Model 2 VA4 and Genesis 3 have it in the 315-5960 / 315-6123 ASIC.
6-channel FM synthesis audio.
Pinout & readings
No pinout or reference readings yet — these show what each pin does and what a healthy part should measure.