Alesis ADAT HD24 - Known Issues and How To Deal With Them

Known Issues and How To Deal With Them

FTP transfers are known to be slower than real-time and not very reliable; this has been attributed to lost DHCP lease. Both of these issues can be overcome by switching to an external file transfer solution. The FTP server of the HD24 is known to hang on occasion; this has been attributed to the HD24 not understanding some of the newer FTP commands (RFC 1639, RFC 2228, RFC 2428) and can be resolved by using an older FTP client or by switching to an external file transfer solution.

Power outages during recording may result in lost recordings, leaving the drive in a corrupt state. This is due to the allocation information of a song only being written to disk when STOP is pressed. The power loss problem can be addressed by powering the HD24 recorder via a UPS. It would be possible to pre-record silence with the expected length of the recording or longer, however Yahoo forum users have reported that this increases drive activity during recording, which increases sensitivity to write errors due to high SPL. Often, it is possible to recover the audio that was lost due to power outages.

The HD24 stores adjacent tracks in adjacent sectors. This guarantees minimal drive head movement across the platters of the drive, but fragmentation in the time domain can still occur. As there is a limit on the number of fragments that a song can contain, heavily fragmented drives may cause data loss. This can be prevented by always recording to a freshly (quick)formatted drive. This best practice will also make it easier to recover from power outages.

Hard drives that are kept on a shelf unused for a long period of time may stop functioning and no longer spin up. This is due to the lubricant of the drives setting, and not a problem inherent to the Alesis ADAT HD24 recorder itself. The problem can be overcome by regularly spinning up the drives and by making regular backups.

The Macintosh version of the FST Connect software has only been released for the PowerPC architecture and not universal binary to support the Intel architecture. This was not an issue until Apple released the 10.4.9 update to its operating system.

Some users have reported the HD24 recorder to fall out of record mode when used in extremely noisy environments due to sonic vibrations. This has reportedly been overcome in several ways, among others fixing the hard drive to the chassis of the recorder; placing the recorder on a soft surface (such as a blanket); or simply shielding the recorder from the loud sound. A solution that was reported successful by HD24 users on Yahoo Groups is to insert washers (thin metal rings) under the connector screws. This will slightly push out the connector, allowing it to make better contact.

There is a possible design flaw in the HD24 where the connector is firmly attached by the two screws leaving no tolerance, which means that the caddy remains in tension and can pop out spontaneously or as a result of vibration. It is possible to work around this by loosening the two retaining screws for the D type connector at the back of the disk caddy. See picture.

A frequently reported issue on the HD24 groups is IDE drives not mounting. There is some speculation about why drives would not mount, and this issue has been discussed extensively by the HD24 group. Alesis confirmed (in thread "WD PATA drive not recognized" in the Yahoo HD24 forum) that larger WD drives do not mount because "their RPM speed is reportedly not as fast as advertised". Other possible causes are believed to be:

• Drives drawing too much current- to address this, a drive compatibility list has been compiled in the files section of the HD24 Yahoo group. Additionally, Alesis/Numark have issued a design update, which adds a capacitor to the drive bay daughterboard (part number 9-79-0238, previously 9-40-0238). This design update is available in the files section from the HD24 yahoo group.
• Removing the drive before unmounting it (unmounting the drive powers it down); This is thought to possibly cause damage on the IDE daughterboard .
• The electrolyte capacitors of the daughterboard drifting out of spec. This could be addressed by replacing the daughterboard or just the capacitors.
• A problem with the drive detection algorithm ("HD reset failed check jumper" error message), mostly with brand new drives. Members of the HD24 Yahoo groups have worked around this issue and had success mounting such drives by formatting them on a PC prior to using them in the HD24.

The IDE connector inside the caddies does not always exactly fit with the IDE connector of the drive. Symptoms are a constantly lit LED on hot-swappable ViPower drive bay, slow booting and the drive not being recognized, either by the HD24 or by the computer. If this occurs, swapping the drive to another caddy may help.