i have a 1989 Sundance Cameo with the Sentry 605 control system.

i turned off the circuit the other day to change a light and i noticed that though the connection indication lights (the two orange lights) went off and the pumps didn't work but the LED's on the topside panel were on and acting wiggy.

a day later i turned the spa breaker back on to test the new light and then turned off the breaker. but the LED's still work, the spa light still gets power, and now the orange connection indicator lights inside the control panel were still on.

what does this mean? is this just residual electricity inside my system? or is this thing still live and ready to shock me?

Generally the capacitors on the circuit board may hold power for a few seconds after complete power disconnection, but they won't last long and the unit will go dead very shortly. If you have a GFI breaker that you are turning off, do a voltage check on the load side (hot tub side) of the breaker after you turn it off. Check both between both hots, and then from each hot to neutral. I have seen some GFI breakers leak voltage past when they are damaged internally, most often due to improper wiring at some point in time. I had a Cutler Hammer 50A GFI that never disconnected one side of the power after it went bad, yet it would still trip with the test button. That same breaker, however, wouldn't trip if you threw the power cord into a bucket of water! Now talk about safe.... I immedately replaced it with a Square D. If your topside is showing display for any length of time after you turn the breaker off, I would suspect you still have power going to the spa.