The crOwBX project: Modifying the
HAA15-0.8-A for +/-19VDC
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The crOwBX requires a +/-19VDC power supply as the boards use local
voltage regulators to obtain +/-15V and +5V for the host board. The
Power One HAA15-0.8-A linear power supply, which is well-suited to
operating the traditional +/-15V modular setup, can be modified to
provide +/-19V by simply soldering a 10K 1% resistor across R20 and
another 10K 1% resistor across R28 on the power supply board, as shown.
The trimmers R21 and R26 are then adjusted such that +19.00V and -19.00V
are observed on the DC output pins with respect to common. Be careful
not to wire this power supply to +/-15V hardware!
NOTE: Some editions of this power supply come with jumpers VW1 and VW2
installed for +/-12V operation. These jumpers need to be cut as
shown. Using the wiring terminals along the bottom of the board for
reference (see board image), VW2 is located just above the "-S" terminal
and VW1 is located just above the "+S" terminal.
The 4-voice crOwBX draws 420mA at +19V and 380mA at -19V, well within
the load range (600mA per rail) of the modified HAA15-0.8-A.