Measuring field output pin voltage IC601/LA7841 basic normal (2 feet low voltage is 2.7V), measured IC201/LA76832 indeed 23 feet (field output) voltage is normal, but only 24 feet voltage 1.5V (aircraft sawtooth the formation of the foot, the normal voltage of about 3V) forms a capacitor C519 aircraft sawtooth kick the 5V supply, 5V measuring its not normal, replace IC703. troubleshooting.TYXservice manual download site