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    ST-70 driver board cover installation shortcut



    Posts : 20
    Join date : 2013-08-27

    ST-70 driver board cover installation shortcut

    Post by fmorelli on Thu Dec 27, 2018 9:06 pm

    This evening I installed the driver board cover, which came with very thorough instructions. I found that I was able to easily install the board without having to actually remove it. I wanted to pass along a few points on how to do this, for those that are installing this on an already finished amplifier.

    • First of all I removed the tubes, the bottom cabinet (4 screws), and then hung the front half of the amp off the table so I could reach the board. The amp stays in place since the heavy transformers are on the back half of the amp, which remains on the table.
    • Unscrewed the four screws that hold the board. There is a locking nut underneath. For each screw, there are also two nuts (which act as standoffs) in between the board and chassis. Press on the board with one hand so that the two middle screws are sandwiched between the board and chassis. Carefully unscrew and remove the screw. Repeat this for the remaining 3 screws.
    • If any of the nuts moved around, use a couple toothpicks to line them back up and center the holes in the chassis and board.
    • Set the cover on the board.
    • Press up on the board to keep pressure on the nuts. Make sure they are lined up with the screw holes.
    • Start each of the 4 screws, and run them at least through the two nuts.
    • Make whatever adjustments to the cover which lines up. The most important line-up is that one can reach the bias adjusters. Tighten the four screws so they lock the top cover in place.
    • Flip the chassis around now, so you can see the board. I stood the chassis on its side.
    • I took a 9/32" 1/4" drive socket and put a small magnet inside. Run the remaining four capture nuts on the posts. You're done!


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