Alesis MultiMix Hum

Blake

The following information addresses how to repair a power supply issue with the Alesis MultiMix. I first noticed the problem about a 7 months ago.

Symptoms are as follows:

  • Clip & Sig LED are on solid (FX section)
  • XLR Inputs hum
FX Section
Here are the LED’s lit up. If you try using the FX section, it hums.

The XLR input hum is the worst problem in my case. So after some Googling and reading, problem is that 2 of the power supply capacitors are blown. To change the capacitors is fairly simple. First thing is to remove the screws on the bottom and the back of the mixer as shown below.

Rear Screws
Remove all the screws on the bottom of the mixer
Three rear screws on the mixer.

Now that the rear plate is loose, disconnect the black 8 pin connector to the power supply, then disconnect the 2 pin SPDIF connection to the main bored on the right.

Disconnect the black 8 pin connector.
Disconnect the 2 pin SPDIF connector.

There should be enough room to get a fillips screw driver in there and remove the power supply bored. But first the connecting wires need to be disconnected.

From left to right:

  • Power Connector
  • Power on/off switch
  • Phantom Power switch
  • Main power to the the mixer
Next step is to remove the 4 screws from the power supply bored. You will need to pry off the components from the heat sink.
Right capacitor has the bottom blown right out of it & the left one is leaking at the top.

As many posts online have said, both capacitors are going to need changing at the same time. Here are the specs of the capacitors. Voltage doesn’t matter to much.

Right Capacitor – 1000uf @ 35V

Left Capacitor – 2200uf @ 35V

My local electronics shop had the right capacitor in stock but I had to use a 50V cap on the left one. It was a little bit bigger so my new cap sits a little sideways on the bored.

New capacitors are installed. You can see the left cap had to be a little to the left so the top part of the mixer would clear.

That is it. You have now successfully change the 2 capacitors causing the hum in your mixer. Follow these steps backwards to put your mixer back together.  Be sure to evenly apply pressure  to the heat sink. Also, when putting the base plate back in, be patient, it will slid in together easily.

Installing NetBeans on Xubuntu 10.04

Blake

Installing NetBeans is simple in Ubuntu, but Xubuntu doesn’t seem to have the package in its repositories. The following will guide you through the install.

First thing needed is Java. You can install the openJDK or the sunJDK.

For openJDK

sudo apt-get install openjdk-7-jdk

For Sun JDK

sudo apt-get install sun-java6-jdk

Next we need to download the NetBeans installer. Navigate to NetBeans.org and download the version you require.

After the download has completed run the following to begin the install.

sudo sh ./netbeans-x.sh

Replace x with the version you have downloaded.

And that is it! You now have NetBeans installed.

VirtualBox Guest Additions install Kubuntu 10.04

Blake

Install VirtualBox’s guest additions are relativly stright forward in Ubuntu. But for Kubuntu 10.04 it’s takes a little more work.

Open the terminal and execute the following commands. First, check to make sure the system is up to date.

sudo apt-get update
sudo apt-get upgrade

Restart the system after these have been installed. Next we need to install and get a few things.

sudo apt-get install dkms
sudo apt-get install build-essential

Restart the system again.
Now we can install the guest additions. Devices -> Install Guest Additions… Virtual CD should mount automatically.

cd /media/VBoxLinuxAdditions_x
sudo ./VBoxLinuxAdditions.run

Install might take a little while to compile. After it has completed, restart the system. Guest additions have now been successfully installed.

Linux Mounting Partitions

Blake

Most Linux distribution include auto mounting for different file system types. Specific distributions, you need to mound some file systems your self. The following commands will allow you to mount different file system types.

To list all partitions attached to the system, use the following commands.

fdisk -l

First thing, create a mount point for this new file system.

mkdir /media/drive

You can create this folder anywhere on the system. Most distributions mount all drives to /media.

Mounting FAT or FAT32:

mount -t vfat /dev/sdb1 /media/drive/

Mounting NTFS:

mount -t ntfs-3g /dev/sdb1 /media/drive/

Un-mounting the drive:

umount /media/drive/

Backtrack 5 MAC Changing

Blake

I have been playing with backtrack5 lately and there was one little issue I was starting to get irritated by. When spoofing your MAC address you were required to run all these commands to take the interface down. First is to stop airmon-ng then to take the interface down. The following script is going to do the following:

Note: Before running this script run ifconfig and find the device name for your wifi card. In my case is is wlan0. If your’s is different then change wlan0 to you device name.

  1. Shut down airmon-ng
  2. Shut down interface
  3. Change the MAC to 00:11:22:33:44:55
  4. Start interface
  5. Start airmon-ng
After the script is complete it will print the new MAC.
#!/bin/bash
echo "Shutting down wlan0..."
airmon-ng stop wlan0 > /dev/null
ifconfig wlan0 down > /dev/null
maccchanger --mac 00:11:22:33:44:55 wlan0 > /dev/null
echo "Starting wlan0"
airmon-ng start wlan0 > /dev/null
string=`macchanger -s wlan0`
echo "Changed MAC to: ${string:13}"

If you have any problem, drop me a line at info@blakemiller.ca