HR-16/HR16B Service Manual 1.00 16 Intermittent reset. (cont.) R28 (reset threshold) is wrong value. (Revision AQ only). Add another 3K resistor in parallel (see section 7.17). Other faulty component is 8031 reset circuit. Troubleshoot and repair as necessary. No sound at all. Faulty DM3AG ASIC, PCM-54 DAC, 4052 analog switch, or op-amp. Troubleshoot and repair as necessary. Faulty volume slider. Test AUX outs. Repair as necessary. User error (i.e. drum pads set to wrong outputs, volumes set to )etc.). Check operating parameters. No sound from a particular drum. User error (i.e. drum pads set to wrong outputs, volumes set to )etc.).
This is particularly noticeable on drums that panned hard left or right (TOM 1 and TOM 3 of the default drum kit). Check operating parameters. Adjust them as necessary. Dirty, or broken cliff (1/4") jack. This is particularly noticeable on drums that panned hard left or right (TOM 1 and TOM 3 of the default drum kit). Troubleshoot and repair as necessary. (see section 7.3) Faulty Analog switch. Troubleshoot and repair as necessary. Faulty op-amp (U20, U21) or component in surrounding circuitry. Troubleshoot and repair as necessary. Component failure in keypad circuitry. (This is actually fairly rare, but it can happen). Troubleshoot and repair as necessary.
(see section 3.3) Intermittent buttons. Old keypad PC Board. Replace with new style keypad PC board and retest. Dirty rubber keypad. Clean keypad contacts with non-residue cleaner (such as Blue Shower). Faulty ribbon cable. Replace and retest. No (or intermittent) MIDI out. Needs MIDI pullup resistor. Add if necessary (see section 7.7). Faulty Transistor (Q1 or Q2). Troubleshoot and repair as necessary. Faulty 8031. Troubleshoot and repair as necessary. No (or intermittent) MIDI in. Faulty opto-isolator (U4). Replace and retest. Threshold resistor (R5) wrong value. See section 7.6. Faulty 8031. Troubleshoot and repair as necessary. No tape out. Broken 1/8" jack (J6). Replace and retest.
User error. See section 5.3. Faulty 8031. Troubleshoot and repair as necessary. No tape in. Broken 1/8" jack (J5). Replace and retest. User error. See section 5.3. Faulty 8031. Troubleshoot and repair as necessary. Faulty integrator capacitor (C11 or C23). Replace and retest. Faulty comparator (U1). Troubleshoot and repair as necessary. Data slider not working at all. Faulty slide potentiometer. Replace and retest. Broken wire between slider and keypad PC board. Faulty ADC circuit. (Usually if this is the case, the keypad velocity will not work either.) Troubleshoot and repair as necessary. (see section 5.2) Faulty 8031. Replace and retest. Data slider skipping numbers. Faulty ADC circuit.
(most likely a short or open in the binary weighted resistor network). Troubleshoot and repair as necessary. (see section 5.2) Foot switches not working. Broken cliff (1/4") jack. Troubleshoot and repair as necessary. Faulty 8031. Replace and retest. Not retaining memory when power removed. (No battery backup. Battery is dead.) Faulty SRAM bypass capacitor (blue monoblock type). Replace capacitor and battery. Check battery current (see section 2.1). Faulty or incorrect SRAM. See section 2.1. SRAM not in standby mode while power off (CE pin 20 not held high). Troubleshoot and repair as necessary. Faulty battery. Replace capacitor and battery. Check battery current (see section 2.1).
Not retaining memory when power removed. (No battery backup. Battery is not dead.) Faulty reset circuit (not going into reset during power down). Troubleshoot and repair as necessary. Faulty SRAM. Replace and retest. Drum pads not sensitive to velocity. Broken Piezo lead. Troubleshoot and replace as necessary. Faulty cable. Replace and retest. Faulty ADC circuit. Troubleshoot and repair as necessary. Unit "crashes" constantly. Faulty reset circuit. Troubleshoot and repair as necessary. Faulty 8031, EPROM, or SRAM. Open or short in address or data busses. Troubleshoot and repair as necessary. Faulty DM3AG ASIC pulling down data buss.
Complaint Possible Cause Solutions Unit "crashes" constantly. (cont.) Faulty I/O latch pulling down data buss. Troubleshoot and repair as necessary. Faulty front panel cable. Replace and retest. Incorrect data slider wiring. Check slider wiring. Repair as necessary.