My Quickie power chair has been in the repair shop repeatedly my chair abruptly stops in traffic and this chair is still under warranity. This chair stops where ever and it is not safe this chair about 7 months old but the last 8 weeks has been awlful.The joy stick box and cable have been replaced 3 times no chang a pin at the back replaced no change i can only get about 2 kil. before i start having trouble i will never by a Quickie again this chair is going to get me killed 1 of these days HELP.CarolAnn