Alesis HR-16 Service Manual page 23

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