The Oki ADPCM chip we use is very sensitive to noise on the +5 line (this is
because the D/A is fed from +5). I recommend that we start using an RC filter
on the +5 to this chip to reduce the noise. Values of 33 ohms and 47uF seem to
work fine. Do not increase the resistor value much beyond this or you may
induce CMOS latchup in the chip.

	Tim