TABLE OF CONTENTS PREFACE..................................................................................................... ii READ THIS! ................................................................................................. ii WARNINGS.................................................................................................. iii SAFETY SUGGESTIONS............................................................................ iv General Troubleshooting.............................................................................. v 1.0 General Description ...............................................................................
1 1.1 Main PC Board Revisions ................................................. 1 2.0 Power Supply ......................................................................................... 1 2.1 Battery Backup .................................................................. 2 2.2 PUP Circuit........................................................................ 2 3.0 The 8031 ................................................................................................ 3 3.1 Reset ................................................................................. 3 3.2 Memory Mapped I/O..........................................................
4 3.3 Keypad I/O......................................................................... 4 3.4 MIDI I/O ............................................................................. 4 4.0 DM3AG ASIC ......................................................................................... 5 4.1 Mask ROMs....................................................................... 5 5.0 Analog Signal Paths............................................................................... 6 5.1 Drum Signal Output........................................................... 6 5.2 Piezo/Data Slider Input......................................................
6 5.3 Tape I/O............................................................................. 6 5.4 Tape Output....................................................................... 7 5.5 Tape Input ......................................................................... 7 6.0 Test Procedures..................................................................................... 7 6.1 General Testing................................................................. 8 6.2 Internal Diagnostics and Hidden Keys .............................. 8 6.3 DAC Adjustments ..............................................................
8 7.0 Updates and Corrections ....................................................................... 9 7.1 New SRAM Supply Circuit................................................. 9 7.2 Glass Zener (D15)............................................................. 9 7.3 Dirty Cliff jacks................................................................... 10 7.4 Ground CE......................................................................... 10 7.5 RF resistor......................................................................... 10 7.6 10K MIDI Resistor (R5) .....................................................
11 7.7 MIDI Pullup........................................................................ 11 7.8 RF Shields......................................................................... 11 7.9 LCD Contrast Adjustments................................................ 11 7.10 DAC Drift ......................................................................... 12 7.11 Old Keypad PC Boards ................................................... 12 7.12 Lifting R41 ....................................................................... 12 7.13 Reset Capacitor............................................................... 12 7.14 Sram Capacitor ...............................................................
12 7.15 Tape Capacitors.............................................................. 13 7.16 RF chokes ....................................................................... 13 7.17 AQ reset threshold .......................................................... 13 7.18 AQ R116.......................................................................... 13 7.19 Volume Slider Wiring....................................................... 13 7.20 PUP Capacitor................................................................. 14 8.0 Common Solutions.................................................................................
15 9.0 Service Parts List ................................................................................... 18 10.0 Software History................................................................................... 20 11.0 MIDI Implementation ............................................................................ 23 12.0 Service Manual History ........................................................................ 31 INDEX........................................................................................................... 32 HR-16/HR16B Service Manual 1.00 vi 03/31/06