Sharp IS471 Frustration

I am trying to figure out how I can be goofing up a circuit that only
has three parts.  I am trying to use a Sharp IS471F  IR proximity
detector module.  Here is the data sheet:
http://www.junun.org/MarkIII/datasheets/IS471F.pdf  .

If I am reading the sheet correctly, the two bent leads are power (Vcc)
and ground (GND) with power being the bent lead closest to the edge of
the sensor.  The other two leads are voltage output (Vo) and light
ground (GL) with light ground being the lead nearest an edge of the
sensor (and furthest from the power lead).  The "outline dimensions"
drawing on page 1 of the data sheet shows Vcc as pin 1 on the left
side.  I am guessing that the view is looking at the sensing side of
the device (i.e. the sensing surface is the flat face of the device).

On page four of the data sheet, there is a schematic marked "basic
circuit".  It shows an LED (assumed IR since the sensitivity peak in
the chart just above the schematic is around 940 nm) connected between
Vcc and GL (assumed GL since the same internal schematic is on page 1
with the GND and GL location marked) and a 0.33 uf cap between Vcc and
GND.

I expected that if I made this circuit and had the IR LED pointing at
the smooth face of the sensor I should get a difference in voltage at
Voc depending on whether I stuck something between the LED and the
sensor.  Nope.  I tried taking readings with a voltmeter and again with
a logic probe, always near 0V relative to GND.

I also expected to get a pulse indicated when I  put the logic probe to
GL.  Nope.  Constant high reading.  A voltmeter shows the voltage at GL
to be about 1V lower than Vcc (4.3V vs 5.38).  Looking at the LED with
a cheap camera that has no IR filter, I can see that the LED is on.

The frustrating thing is that I did get this to work a few months ago.
I had some problems then too, but it did eventually work.  I have no
idea what I did different this time.

Any ideas?

Paul  Pawelski