hi there belinda..the problem with the 420 model is that the chair/carriage that runs up and down the rail picks up a charge from a copper strip at the back of rail, this is called a buzzbar,sometimes the brush that picks up the charge from the buzzbar can get dirty and cause the stairlift to bleep, in your case it seems that as you turn the chair around at top the added wait leans the carriage over slightey causing the stairlift to bleep,,this is just telling you that there is no charge getting to the carriage batteries at this point,don"t worry this is common on this model just swivel the chair back round and move the lift down slightley..if it continues the buzzbar will need either cleaning or adjusting hope this helps........paul portsmouth u/k
PAUL, September 2013
