And on the matter of fans, my 5245M fan has been replaced for some time--well worth the bucks. Same goes for any other test gear with noisy fans-I just replace the fan- they're cheap enuff these days. I would endorse the comment re changing out power supply electros too- its often quite revealing to check dc supply rail ripple first -- if you need some encouragement to get started! 73 Dave, ZL3FJ