Adventures in creating and destroying sounds
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  • Replacing a non-operational motor on a Tascam Portastudio 424 MKII

    Posted on February 10th, 2009 Bob 38 comments

    tascam_portastudio_424_mkiiI was fortunate enough to pick up a used Tascam Portastudio 424 MKII about 4 years ago on Craigslist. It worked flawlessly when I first got it. Recorded many a Xome tracks on the beast and eventually set it up so that the output of the 4-track was plugged into the soundcard on my computer. It was so handy having this setup to try out new gear and record that the Tascam almost never was powered down.

    I decided to check out some old 4-track tapes recently and noticed that when I pressed play, rewind or any of the other tape transport buttons that the appropriate light would come on for a few seconds, some clicking was heard but it pooped-out.

    I decided to open her up and poke around a bit. I noticed that the motor underneath the cassette tape bracket seemed like it wasn’t moving when perhaps it should. After taking out the bracket and looking at the motor, I did a quick Google search on the part number printed on the motor’s label (which proved not as fruitful as I thought it might be). But I finally found a place in Indiana called Studio Sound Electronics that carries the exact replacement. I found from the information on their site that it was a 12-volt Mabuchi motor. I placed 12-volts on the motor and yup, no movement.

    I decided to order a replacement from Studio Sound Electronics. The motor was $9.95
    And shipping to California was just under $5. I must say that Studio Sound Electronics’ service is wonderful. The motor arrived just a few days later.

    I popped in the new motor, soldered the 4 wires into place and put everything back together. Bam! Works like new again!

    Here are some hints if you’re looking to do this repair yourself:

    ** There are about 15 screws on the bottom of the unit that need to be removed including one that is on the little “ledge” on the back of the 4-track.

    tascam_openhood** After carefully opening up the unit, you have to disconnect 5 connectors – 4 from the big circuit board and one two-position connector from behind the transformer. Since they are all different positions and there are slots so you don’t put them in backwards, it’s not really necessary to mark them or anything like that.

    tascam002z** Remove the connector from the back of the cassette tape bracket.

    ** Remove the entire bracket assembly with the screws on the top of the bracket.

    ** Remove two screws on each side of the bracket to access the bottom bracket that holds the motor. One on each side is screwed through a plastic clip thing. tascam002You might want to put these away carefully so that you get the plastic clips on the correct sides when you put it back together.

    ** Move the motor’s belt over to the side and remove the 3 flat-headed screws that mount the motor. Gently pull off the belt guide.

    ** Once the motor is free, cut the 4 wires connected to the motor. You may want to memo where each of the wires go. The wires go as follows: A: blue, B: yellow, +: red, -: black.

    tascam_motorback** Strip each of the wires (about 3mm will do) and solder the wires on to the new motor.

    ** Putting the 4-track back together is the reverse of taking it apart. Just make sure you have all your electrical connectors connected!

    tascam_motor** The motor in the Tascam 4-track is a Mabuchi Motor EG-530KD-2B. It’s a 12VDC 1600/3200 RPM CCW (counter clock-wise rotation) motor. It’s available from Studio Sound Electronics at