Charger input passes through the same circuitry as the output to the plug. The Fireplug should be charged with the control set all the way to the right. This sets the potentiometer to 0 ohms, so full charge current gets to the battery. If he tried to charge it with the control to the left it won't charge. The ammeter is inductive. It has a simple of coil of wire around it which creates a field to cause meter deflection. No power goes through the actual meter movement.

The two most common failures (besides the actual cell itself) are an open fuse or dirty windings on the pot. The fuse is actually the connection between one terminal on the battery cell and a terminal on the top of the unit. Check it with an ohm meter. If the pot is dirty, many times just moving the lever back and forth multiple times will clean it. Otherwise, a few swipes with 400 grit paper will shine it up.

If the unit will still light the plug, then it is fully functional. If not, try removing the cell and hooking the charger directly to it. No joy here means either bad battery or bad charger.

Thanks, guys. This info helps.

I will pass on the info about the fuse, the position of the rheo for charging, and the inductive pickup on the ammeter. I wondered if it had a shunt resistor, so thanks for clarifying.

Be nice if he gets to use it again.

Dave

Bill,

It probably won't be used for racing, but it still might blow at the worst possible time--right when you finally got on the circle and want to go....

Had something similar happen to my (very) well used Radio South Pro Driver. No more glow and no more go. When I opened it up, the FET had smoked. I must have shorted it somehow. I had two and they lasted a long, long time.

I'll let him know about the fuse.

Thanks,

Dave