Alesis HR-16B Drum Machine Take Apart
Vintage Alesis HR-16B Drum Machine. 47 sounds. 16-Bit quality. 1989. Main sound board. The case is a cheap tupperware type plastic with a paper foil for RF shielding. The hardware is identical to the HR16 introduced in 1987 except for the wave ROMs. It is made in USA with no surface mount components, only DIP IC's on a double sided circuit board. An 8-bit 8031 microcontroller running at 12 Mhz (probably only 2 Mhz cycle speed) with with 32K ROM and 32K RAM (to the left of the CPU). The DM3AQ is a special ALESIS ASIC that generates the sounds from the two Wave ROM above it. The D/A convertor is beside it. The 3.6 V 1/3AA Lithium backup battery is still going after 21 years. The piezoelectric discs are for sensing velocity of the keypads. RIbbon cable connect to the main board. For an 8-bit machine, the user interface is quite responsive unlike the latency of software machines today.
http://www.facebook.com/photo.php?pid...