bluercpilot
02-18-2008, 04:17 PM
I discovered another hazard yesterday. After running two batteries through my B400, I set the heli down and put in a third. When I connected the third battery nothing happened. No power to the heli at all. I tried both of the other batteries. Same thing. Off to the workbench.
I used a multi-meter to determine that there was a cold solder joint on the positive wire where it joined the connector. For those of you not familiar with the term, a cold solder joint occurs when the solder joint isn't allowed to properly cool or isn't heated to an adequate level. It can, and in this case did, result in an open connection. A properly soldered joint will have a smooth and bright shiny appearance. Cold joints usually look rough and dull.
When I pulled the connectors out of the plug and examined them, it was clear that the pins had been improperly soldered. There wasn't enough solder in the pin opening and what there was clearly looked like a cold solder joint. I resoldered both connectors. That took care of the problem.
Obviously, if this joint had electrically opened in flight I'd have been in real trouble as I'd lost all power to the servos. Fortunately, it must have opened when I removed the previous battery. Using the multi-meter allowed me to determine the cause - otherwise I'd have suspected a bad ESC.
I'd recommend you examine the backside of your ESC connector and, if it looks at all suspect, remove the pins and resolder them. By the way, removing the pins is fairly easy. Just grab them with needlenose pliers from the front of the plug and work them out. Putting them back is the reverse.
I used a multi-meter to determine that there was a cold solder joint on the positive wire where it joined the connector. For those of you not familiar with the term, a cold solder joint occurs when the solder joint isn't allowed to properly cool or isn't heated to an adequate level. It can, and in this case did, result in an open connection. A properly soldered joint will have a smooth and bright shiny appearance. Cold joints usually look rough and dull.
When I pulled the connectors out of the plug and examined them, it was clear that the pins had been improperly soldered. There wasn't enough solder in the pin opening and what there was clearly looked like a cold solder joint. I resoldered both connectors. That took care of the problem.
Obviously, if this joint had electrically opened in flight I'd have been in real trouble as I'd lost all power to the servos. Fortunately, it must have opened when I removed the previous battery. Using the multi-meter allowed me to determine the cause - otherwise I'd have suspected a bad ESC.
I'd recommend you examine the backside of your ESC connector and, if it looks at all suspect, remove the pins and resolder them. By the way, removing the pins is fairly easy. Just grab them with needlenose pliers from the front of the plug and work them out. Putting them back is the reverse.