OK, I tried here a few months ago and got no replies so here goes again.
I have an Aeroflex IFR 3413 sig gen which displays an error, the error is unlevelled.
After running the unit for a period of time the RF module gets very hot, output from it is very low and distorted.
I suspect the output drivers are toasted, the heat appears to be coming from two linear regulators which supply power to the output devices.
Lifting the inductor that feeds power from said regulators to the output devices stops the heat generation and measuring from supply connection to ground shows a very low resistance for both output devices.
I've had no luck sourcing or even identifying the devices and the manufacturer does not publish, to my knowledge, schematics so I can't rely on a part number to find an alternative.
I need to draw out the schematic of the output stage but I think it varies the level of amplification by changing the applied voltage to the push pull final devices, does this sound like a reasonable method to the highly experienced RF guys here?