The smoke escaped!
 

I had something happen today I have never had happen before.
I have a Super Sportster 40 I have flown 1 time, and was very happy with.
I field charged it today, hoping the wind would die down a bit. It seemed to take a long time charging (2500mah NiMH onboard battery), but it finally got done, putting 1400maH into the pack. When I turned the switch on, smoke poured from the servos!. I immediately unplugged, and looking at the thing, there was a puddle of liquid--gray-brown-yellowish stuff in the servo compartment. When I tipped it up to dump it, it turned out to be a very heavy vapor.
I got everything home, and the Spectrum Receiver checks out perfectly fine (using a different battery, of course). I'm concerned about plugging any of the servos in to ANY receiver. (2-JR L501's and an L502)
Any idea what the hell happened?

Are you sure the smoke came from the servos and not the pack? I'll bet that brown goo came from the pack also.

Well, the pack is at the front end (I have not pulled it yet) and the goo-looking stuff was in the servo compartment (past 2 bulkheads)--But I'll check it out...

Apparently one of the L502's shorted out. The other 2 work fine, but the throttle servo, when plugged in, immediately cause the lights to go out on the rcvr, and the wires get hot.
Battery checks out right now, but I will be checking it very closely and making for sure that it is good...

The only electrical things in a plane that would expel yellow/brown goo are batteries or capacitors. I think if the servos took the amount of voltage/current to smoke/melt them that the receiver would also be toast.

Yeah. That's what has me concerned. I need to break out the diagnostics tools, but its hot and buggy out here tonight...

What voltage are the servos rated for?
What was the end of charge voltage of the Battery?
Generally, the "goo" indicates that a very high current condition existed.
(Not to mention the smoke)
It's quite possible that servos rated at say 5 to 6V saw a higher voltage, and the internal capacitors blew, resulting in the "goo",
and a high current short. It may be possible to dissect a servo that has some goo around it, and check for vented/blown capacitors.
It's even possible that replacing the bad capacitors might repair the servo(s).
It's also possible that the shorted components reduced the voltage and confined the damage.