AudioBox 1616HD & AudioBox AB1616

updated 1 September 2005


This manual provides troubleshooting and servicing information for both the AudioBox 1616HD and the AudioBox AB1616.In this manual, "AudioBox" refers to both the AudioBox 1616HD and the AudioBox AB1616.

What to Do First:

Please consult the User's Manual for AudioBox setup information.When an AudioBox that has been set up and working properly later seems to be malfunctioning, do the following:

  1. Verify AC power connection to external power supply
  2. Verify connection from external power supply to AudioBox
  3. Verify power supply is generating the correct voltage (no less than 11.5 VDC and no more than 12.5 VDC)
  4. Verify audio connections and proper functioning of all connected audio equipment
  5. Verify MIDI cabling and connections
  6. Verify SCSI cabling and connections, including SCSI bus termination
  7. Try rebooting both the AudioBox and the control computer or interface

Please read this short document carefully. It contains important information about possible sources of difficulty, tests that may be performed and corrective actions that may be taken.

MIDI Indicator

The MIDI indicator (green LED on the front panel) flashes whenever MIDI data is being received at the MIDI IN port. This occurs whenever the 5 volt power is applied to the main circuit board, whether or not the AudioBox main processor is functioning. The MIDI indicator blinks briefly right when the AudioBox is powered on.

If MIDI data is being sent to the AudioBox but the MIDI indicator is not flashing, check the cables carefully, and check any interface boxes that are connected (some have MIDI indicators also).

SCSI Indicator

The SCSI indicator lights whenever there is activity on either the external SCSI bus, or the internal disk drive bus. The AudioBox main processor must be functioning for the SCSI indicator to work properly. If the SCSI indicator light is stuck on, it is an indication of a processor hang, which could be due to a faulty internal disk drive, a hung external SCSI bus or an internal firmware or hardware fault.

Difficulties with the SCSI connection from the AudioBox to the control computer are often due to improper SCSI bus connections, bus termination or problems with drivers in the host computer. See the User Manual and the Richmond Sound Design web site for more information.

Status Indicator

The STATUS indicator (red LED on the front panel) displays the AudioBox unit status. When the unit is powered on, the STATUS indicator blinks rapidly during the initialization period, which lasts approximately 12 seconds. After initialization, a steady one-second 50% duty cycle flashing of the STATUS light indicates the unit is operating normally.

If the STATUS indicator does not blink (stays on or off), an internal AudioBox hardware fault is indicated.

In the rare event that an unrecoverable error occurs, the STATUS indicator will blink a number of times between a long pause. The number of blinks indicates the error condition, as follows:

  1. not used
  2. RAM test failed - internal AudioBox hardware fault
  3. Firmware exception: bus error, address error, illegal inst. etc. - could be hardware or firmware fault
  4. Internal disk drive didn't come ready - usually indicates bad disk drive
  5. Internal disk command lock didn't become free - usually indicates disk drive is not connected or failed
  6. Internal disk drive controller command in progress bit didn't clear - usually indicates bad disk drive
  7. Internal disk drive controller data buffer ready bit didn't become set - usually indicates bad disk drive
  8. DSP A host interface not responding - internal AudioBox hardware fault
  9. DSP B host interface not responding - internal AudioBox hardware fault
  10. DSP C host interface not responding - internal AudioBox hardware fault
  11. DSP C host interface not responding - internal AudioBox hardware fault
  12. (During ROM bootup only) No HDD responded to INQUIRY - usually indicates bad disk drive

Firmware exception blink sequence

With T262 and later firmware, if a firmware exception occurs, rather than blinking 3 times (as in the above chart), the status light blinks a sequence of numbers useful for diagnosing the fault. There is a long pause before the sequence starts, with a much shorter pause between numbers. The sequence is 6 numbers in length; each number is between 1 and 16.

Startup / Firmware problems

If the AudioBox does not start up properly, the problem can often be resolved by reinstalling the latest firmware, clearing the data on the drive, or both.

These procedures may require setting DIP switches on the main circuit board. The DIP switches are located along the edge of the main circuit board that is nearest the front panel.

Reinstalling Firmware

The lastest firmware is always available on the download page on this web site. See the Richmond Sound Design web site to download the Windows installer and the download page on this web site for the Mac OS installer. Instructions for running the firmware installers are included in the downloads.

In an AudioBox with the current ROM version, DIP switch #4, when set, prevents the AudioBox from reading data from (but not writing data to) the disk. Data on disk includes firmware as well as audio and show files. With switch #4 on, the AudioBox will wait indefinitely after power up for a firmware download, instead of the normal behavior, which is to read firmware from disk after the 12 second disk spin-up period. Running the first procedure below will indicate which ROM is in the AudioBox. The alternate procedure is used when the AudioBox contains the older ROM.

Procedure to reinstall firmware

  1. Obtain lastest firmware and installer program from web sites
  2. Remove power from the AudioBox
  3. Remove the top cover
  4. Set DIP switch #4 on the main circuit board ON (leave SCSI ID switches, #1 - #3, as they were)
  5. Restart the AudioBox; status light begins to fast-blink
  6. Wait for initialization sequence to complete (at least 12 seconds)
  7. If after 12 seconds the status light does not continue to fast-blink, follow the alternate procedure below
  8. Install firmware (no time restictions)
  9. Power down AudioBox
  10. Set DIP switch #4 on the main circuit board OFF
  11. Restart the AudioBox and test for normal operation.

Alternate procedure:

With older versions of the AudioBox ROM, DIP switch #4 does not prevent the AudioBox from reading firmware. In this case, assuming there are startup problems, the firmware download must be started within the initialization sequence (the first 12 seconds after power is applied):

  1. Boot host computer with the AudioBox running, even if it is in an error blink mode. (This step not required on Mac OS 9 and earlier.)
  2. Turn off the AudioBox
  3. Launch the firmware installer program so that it is ready
  4. Restart the AudioBox
  5. As soon as the status light begins to fast-blink, start the firmware download (must start within 12 seconds)
  6. Wait for normal status blink (wait at least 20 seconds after power was applied)
  7. Power down AudioBox
  8. Return switches to prior settings
  9. Restart the AudioBox and test for normal operation.

Clearing data on the disk drive

If there are still startup problems after reinstalling the firmware, there may be corrupted data on the disk. The following procedure will completely clear all data from the disk. Note that all audio and show files will be erased.

  1. Remove power from the AudioBox
  2. Set all four DIP switches on the main circuit board ON
  3. Restart the AudioBox
  4. Wait for normal status blink (wait at least 20 seconds after power was applied)
  5. Power down AudioBox
  6. Return switches to prior settings
  7. Restart the AudioBox and test for normal operation.

Internal Disk Drive

Most hardware-related disk drive failures will result in one of the disk drive-related STATUS error indications listed above. In this case, first verify that the disk drive spins up when power is applied. If not:

Drive does not spin up

Check power voltages to the disk drive. If the are bad, do not reconnect the power connector to the disk drive. Return the AudioBox for servicing.

If the disk drive power voltages are normal and the drive does not spin up, there is either a problem with termination on the internal SCSI bus or a defective disk drive. Verify jumper settings on the disk drive. In most cases, the "terminator power" jumper is required. If the jumpers are correct and the drive still does not spin up, replace the internal SCSI terminator. If this does not correct the problem, a defective disk drive is suspected. If possible, try installing a new or known-good SCSI disk drive.

Other Disk Drive Errors

Perform the procedure to clear drive and reinstall firmware, above.

If the problem persists, if possible remove the disk drive and connect it to a computer that has an external or internal SCSI bus, and run SCSI bus diagnostics. If the disk drive fails these diagnostics, replace the disk drive. If it passes, reinstall the disk drive and contact Richmond Sound Design regarding AudioBox servicing.

Drive Defragmentation

A defragmentation of the internal AudioBox disk recovers unuseable disk space that accumulates as files are erased and re-written on the disk. The only legitimate reason to defragment a disk is to retrieve disk space when a disk is almost full and the recoverable disk space is needed. Defragmenting a disk will not repair a damaged disk directory or correct any other fault condition. Nor will defragmenting a disk make playback work better in any way.


Low-level reformatting of the internal disk drive is rarely indicated, and would only be recommended if there were reason to suspect the disk drive had been damaged, as a way to possibly recover the operation of the drive. However, if a drive is malfunctioning, it is better to replace the drive. Reformatting the drive may only postpone the complete failure of the drive, and the AudioBox may not be able to play back audio correctly with a drive that has had data sectors relocated (one of the possible effects of reformatting). Low-level reformatting can only be done by removing the disk drive from the AudioBox, connecting it directly to the SCSI bus (and power connector) of a personal computer and using a disk utility program on the computer. After a reformatting operation is performed and the drive is reinstalled in the AudioBox, reinstallation of the firmware and is required to restore proper AudioBox function.

Audio Artifacts

There have been occasional reports of audio artifacts in an AudioBox output variously described as clicks, thumps, buzzes, etc. The following is a checklist of possible causes:

  1. Ground loops can exist between the AudioBox and connected equipment. It is especially important that any connected computer be connected to the same AC power source as the AudioBox. If the equipment is in a rack, the rack must be grounded to the same electrical ground as all the equipment in the rack. Other equipment electrically connected to the AudioBox chassis must not inject noise into the ground system, especially if the AudioBox outputs are connected unbalanced. These recommendations hold true for audio equipment in general.
  2. Mixing single-ended outputs with balanced inputs is inadvisable. The reason this causes problems is that the ground coming from a balanced device can be, and often is, a dirty AC ground since it is basically a chassis ground (AC safety ground) that doesn't carry signal. The noise from this ground gets injected into the AudioBox ground system, which is OK as long as the entire system is balanced. But with, for example, an unbalanced output, the ground is being used as a signal ground, and SCSI signal currents can modulate the noise in the grounding system, causing a low-level buzz in the output that correlates with SCSI activity. If everything is unbalanced, no problems have been reported, because single-ended devices have to produce clean grounds. And if everything is connected balanced, which is the obvious recommendation, no SCSI noise has ever been reported in the audio outputs.
  3. Phantom power should never be applied to AudioBox inputs or outputs.
  4. Equalization and delay settings should only be changed on muted channels, as stated in the AudioBox command set and in the documentation for AudioBox control software. In particular, if clicks or thumps are heard at the start of a cue, the cue should be examined to see if it contains EQ or delay commands along with commands that open gain channels. If so, either split the cue or delay the gain commands that open the audio channel or channels by several frames. Digital equalization and delay algorithms can sometimes introduce audible noise (clicks and thumps) at the instant when the parameters to these functions are changed. It is, of course, possible to implement digital equalization and delay functions that are entirely free of these artifacts, but these implementations consume roughly twice the DSP horsepower as the functions that are implemented in the AudioBox. The AudioBox, like many other digital audio processing devices, was designed to deliver the maximum amount of signal processing possible with the available hardware resources, with the understanding that equalization and delay settings are to be kept static on live channels.
  5. Excessive levels can cause clipping, especially if equalization is in use that boosts a frequency band. The AudioBox gain matrix is, technically-speaking, an attenuation matrix, meaning that the gain functions always cut gain, never boost it, making it nearly impossible to cause internal clipping. Another way of saying this is that a fully open channel (input gain at max, crosspoint gain at max and output gain at max) is a unity gain channel from input to output. The audio inputs clip at +20 dBu. With EQ, however it is possible to add gain to selected frequency bands, which makes internal digital clipping possible. Care must be taken when EQ with gain is combined with high signal levels. Playback audio material from the internal disk drive is connected to the matrix input without attenuation. A gain-normalized audio file by definition has at least one full range sample in it; at this point in the file the signal is at an instantaneous level of +20 dBu. If any EQ with gain is added to a channel that has its input level full-on into which is playing back a gain-normalized audio file, clipping will occur.
  6. Distorted audio can find its way into the selections stored on the internal disk drive, either before or during the transfer of the data to the AudioBox. In this case, distortion will always occur in the same playback location (or locations) every time the selection is played back. It is possible to transfer the file back to the host computer, and check for any differences with the original sound file. If problems are occurring during the transfer of files to the AudioBox, it will be necessary to resolve whatever problem exists in the SCSI data chain between the host computer and the AudioBox. Possibilities include software, particularly SCSI driver problems, a bad or loose host adaptor card in the host computer, a bad or loose SCSI cable and improper SCSI bus termination. See the SCSI section in the User's Manual for the proper way to set up a SCSI connection.

Hardware Faults

Perform the following visual checks and voltage checks.

Visual Checks

Remove the top cover to the AudioBox and verify that all internal connectors are seated properly and that there is no obvious physical damage to the unit.Verify that there is no loose hardware.

Internal Power Board Checks

If the incoming power voltage is too high, if it is reversed in polarity or if the AudioBox is drawing too much power for some other reason, the circuitry on the power board (located on the right side panel of the AudioBox chassis) goes into a protection mode to prevent damage. In this mode, a polyfuse (a yellow device that looks something like a capacitor) on the power board heats up, limiting the incoming current. When conditions return to normal, the polyfuse cools down and normal operation is reestablished without requiring that the polyfuse be replaced.

If the incoming voltage is in range and the polarity is correct, a hot polyfuse indicates too much current is being drawn. Turn off the AudioBox, let the polyfuse cool, remove the power plug from the hard disk drive and restart the AudioBox. If the polyfuse remains cool, the disk drive is drawing too much current, and should be replaced. Otherwise, a main circuit board fault is indicated, and the unit should be returned for servicing.

Newer power supply boards contain a yellow LED in the lower corner near the front of the unit. This LED lights when the incoming voltage is too low. If this LED flashes during startup, it may indicate that the unit is drawing too much power or that the external power supply is not providing sufficient current to start the unit. Some disk drive require a fairly large amount of current when spinning up the disk.

Main Circuit Board Power Voltage Checks

The power to the main circuit board is supplied through a four-pin connector that plugs in on the side of the main circuit board closest to the disk drive.There are four wires going into the connector, black, red, white and yellow. The black wire is ground and should be connected to the black (minus) lead of the voltmeter.The other voltages are read with the connector plugged into the main circuit board with the red (plus) lead of the voltmeter as follows:


Nominal Voltage

Minimum Voltage

Maximum Voltage






+12 or +15




-12 or -15



If the main circuit board power voltages are out of range, the unit should be returned for servicing.

Note 1: Some units are equipped with a power supply that produces +/- 12 volts for the analog circuitry and some are equipped with a power supply that produces +/- 15 volts for the analog circuitry. The analog circuitry operates correctly within the entire specified range.

Note 2: With the power connector disconnected from the main circuit board, the voltage readings for a normal power supply may not fall into the ranges specified above.

Disk Drive Power Voltage Checks

The power to the internal disk drive is supplied through a four-pin connector that plugs into the front of the disk drive next to the data cable.There are four wires going into the connector, two black, red and yellow. Disconnect the plug from the disk drive.The two black wires are grounds. They are not connected at the power supply end. To read the 5 volt power voltage, the red (plus) lead of the voltmeter is connected to the red wire in the connector and the black (minus) lead of the voltmeter is connected to the black wire adjacent to the red wire. To read the 12 volt power voltage, the red (plus) lead of the voltmeter is connected to the yellow wire in the connector and the black (minus) lead of the voltmeter is connected to the black wire adjacent to the yellow wire.


Nominal Voltage

Minimum Voltage

Maximum Voltage









If the disk drive power voltages are out of range, the AudioBox should be returned for servicing. If the disk drive power voltages are in range, reconnect the power connector and repeat the voltage readings with the power board connected to the disk drive. The normal ranges are the same. It is nearly impossible to get the probes of a voltmeter into the end of the power connector with the drive installed. However, the readings can be made on the power circuit board at the points where the wires are soldered to the board. If the disk drive power voltages were OK not connected to the disk drive but out of range when connected to the disk drive, a fault is indicated in either the disk drive or (less likely) the power board. If a known good disk drive is available for testing, plug the disk drive power connector into the known good drive. If the voltages are normal, the drive is faulty and should be replaced, otherwise the fault is in the power board and the AudioBox should be returned for servicing.

Warranty / Service

Harmonic Functions Inc., Burnaby, British Columbia, Canada, warrants to the original purchaser that the AudioBox Disk Playback Matrix Mixer (the product), not including the internal disk drive (which is warranted separately by its manufacturer), will be free from defects in materials and workmanship for a period of five years from the date of original purchase. Harmonic Functions agrees, as its sole responsibility under this limited warranty, at its sole option, either to repair, replace, or refund the purchase price of any product discovered to be defective within the warranty period, upon receipt by Harmonic Functions. Any such replacement product may be, at the sole option of Harmonic Functions, a new product or a remanufactured product.

This limited warranty is not applicable to normal wear and tear, abuse, unreasonable use, mistreatment, neglect, damage caused by the equipment or system with which the product is used, or damage caused by modification or repair not carried out by Harmonic Functions.

This warranty and the remedies set forth herein are exclusive and in lieu of all other express or implied warranties (including any implies warranties of merchantability or fitness for a particular purpose) which are disclaimed and no other representations or claims of any nature shall be binding or oblige Harmonic Functions. In no event will Harmonic Functions be liable for any special, incidental, or consequential damages, including, but not limited to, damages resulting from use or malfunction of this product or the equipment or system with which it is used, loss of profits or revenue, or cost of replacement goods.

If you suspect a malfunction in a AudioBox Disk Playback Matrix Mixer, contact your AudioBox dealer for further instructions.