Using this to chip to output proprietary code on the RS-485 bus. The signal is received by another '485 transceiver down the line. The output voltage levels for both +(A) and -(B) lines is 2.5V and signal transmits properly. After a while, the +(A) line goes dead down to a few millivolts. It remains dead with no load applied. Replacing the chip makes it work again. This only happens on +(A).