TR9090, on the case again

Figured it was about time I resumed this project.. I was working on it some time during march but as it was just board parts assembly and toying around with one possible case that never got anywhere, I figured I’ll skip writing a post for it. The case belonged to a awesomely retroish defunct Akai cassette deck..:

The cool retro Akai tape deck

.. Just plain brilliant stuff, so of course I spent a quite a time wondering how this could be turned into a neat housing for the TR9090 boards and a sequencer. I kinda started working on it too, but eventually figured that something rack-stackable might be more usable as it started looking like I’m not going to complete a sequencer for the unit any time soon (read: ever).

As for the assembled boards, they’ve just been waiting for a suitable case to come my way. Surprisingly enough, as far as parts availability is concerned, it was not the rare transistors that proved the hardest to source but the 4000 -series unbuffered NAND CMOS chips (used in hihat/crash/ride circuits). Whereas I had all the other parts gathered up during march, it was these chips that took all the way until a few months ago to acquire. Anyway.. all parts and enclosure ok, so it’s build time! Figured I might try something semi-CADish too.

Potentiometer placement on paper, used as a drilling quide..

..and the sheet of aluminium underneath!

Fancy CAD, so to say :). For the case, I have a old VCR and the sheet of aluminium pictured above is going to replace the its bezel. Or moreover cover it, I’ll just glue it on top. This’ll allow me to hide the potentiometer fastening nuts.

The inner frame of VCR casing with the new bezel.

The case has three parts, these are the outer shell (metal), the inner frame (plastic) and a base plate (metal). As the base plate is detachable with a couple of screws, I figured retaining this “service bonus” would make sense.

Board mounted to the base plate.

Boards stacked to base plate and the whole construct in place.

Power connector and transformer installed.

Should anyone need a service manual for the Akai GXC-45 / GXC-46 tape decks (or their D-variants), I now have one extra. Offers welcome, it’s even in a pretty mint shape ;)

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2 responses to “TR9090, on the case again”

  1. Tim says :


    Is it working ok for you to mount the pcb’s ontop of each other?

    I would like to do the same, but i am scared to get noise.


    • Arto says :

      Hi! I accidentally fried my TR9090 while building it and lost interest to the project. I’ll let you know if I get around fixing it :)

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