[XCSSA] Oscilliscope help?

[X-otic Computer Systems of San Antonio]

I went ahead and got the Propeller dev kit and working with it has
been great so far, however I've come up on a problem.

When I'm trying to read PWM signals with my oscilliscope, it shorts
out the chip and reboots it.  As a test, I used the usb to serial
"Propeller Key" adapter (which is essentially a USB to 3.3V serial
adapter)  as a test and kept transmitting while the oscilliscope was
attached to GND and the Tx pin.

The adapter behaved erraticly and it persisted until the red connector
(sense?) was disconnected from the TX pin of the "Propeller Key".
Neither the Propeller or the Propeller Key seemed to mind the ground
connector being attached.

I'm not entirely sure I know how to set it op correctly, but I know
that I've used it connected to a stereo and have used it in the past
for many other things like that. Is there supposed to be a specific
level of resistance or maybe my settings are off?

No snickering... my oscilliscope is a Telequipment D61 and I used to
have the manual for it somewhere.  Google hasn't been much of a help
with helping me with solving the issue.  I'm not using anything
special, just some generic probes I got from Fry's.

Thanks in advance!  Feel free to ask questions if I forgot something.

FIRESTORM_v1