This is an Icom 746Pro I repaired for a friend. The VHF transmit section was intermittant, and finally failed. This rig had me chasing my tail! First, I found the little potted VHF T/R relay had burned contacts and would not conduct when energized. Once that was replaced, the PA had almost no output. One of the 2SC2694 final output transistors had failed. That was repaired, which then showed drive to be extremely low due to a bad driver MMIC. That was replaced, and it came alive. However, after a bit of use, the transmitter again became intermittant. RF would leave the PA, go to the T/R relay, and disappear under the RF shield that covers the bandpass filter...but nothing out the other end! That area is nearly impossible to work on, since the radio has to be torn to pieces to get the board out, and is inoperable in that condition. I used the dremel tool and sliced the shield open and was able to trace the problem to a hairline crack in a surface mount resistor that supplied the coil voltage to the relay. That was replaced, and all was well. There's no doubt the resistor was the root of this string of failures. I used solder to stitch the shield back together, and it hasn't missed a beat, yet. Here's a few pics....
