Mounting the PSU2 Board to the Panel
The LM337, U2, fitted into a 5U 19” rack panel. Note the grey TO-220 insulator pad underneath the
regulator IC.
The PSU2 PCB needs to be fitted to your chosen panel. Use the PCB as a template for
marking the panel and then drilling the four 3.5mm holes needed for the mounting pillars. The
board should be spaced high enough off the panel with suitable mounting pillars so as to not
short out any of the components' leads should the board be flexed downward, and also not be
too high so that the leads from the regulators can't reach through the board to be soldered. I
find an 8mm spacer is best.
For the four PCB mounting holes, insert a 6mm screw through each of the four holes in the
panel. Fit a star washer over the exposed thread on the inside of the panel. Now fit a hex male-
female 8mm spacer over the washer and tighten. Check that the four holes in the PCB line up
with the threaded tops of the hex spacers by temporarily fitting the PCB onto the spacers.
Loosen and re-align any spacer if it does not fit properly.
Now you need to prepare the leads of the two regulator ICs. The three legs need to be bent
upwards so that the PCB can be fitted over them. Note that the top surface of the device is
marked with the name of the component and it is the flat side on the bottom of the device that
will be in contact with the panel. You should be able to see that the leads have a thicker
section close to the body of the device. Make a ninety degree bend upwards at the point where
the lead thickness changes. Do this for all three legs of the device.
Remove the board from the panel and fit the regulators to the board by poking their legs up
through the bottom of the board. Do not solder them and fit the board back into place on the
panel. Use the hole in each regulator's metal tab to mark out where you need to drill the
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