so this has been sitting on my bench for about three weeks now and i keep putting it off but finally pulled the covers off today. picked it up at a hamfest for basically nothing because the guy said it had low power output and he didnt want to mess with it. i figured it would be a fun project.

anyway hooked it up to my dummy load and watt meter and yeah, its doing maybe 8-10 watts on a good day across all bands. drive level seems fine, ALC is behaving more or less how i'd expect, the display and everything else works fine. RX sounds great actually, really clean. so im pretty confident the problem is somewhere in the PA stage and not upstream of that.

opened it up and one of the 2SC2290 transistors looks a little sus to me, theres some discoloration on the case that i dont love the look of. havent pulled it yet to test it though. before i go yanking parts out i just wanted to see if anyone has been down this road with a 757 before, any gotchas i should know about? also wondering if its worth going with the stock transistors or if theres a better drop-in at this point since the originals are kind of a pain to source.

yeah the 2SC2290s are getting hard to find and when you do find them theyre sometimes questionable quality fakes. lot of people have had good luck with the MRF476 as a substitute, takes a little work to get the bias right but its doable. definitely check both transistors even if only one looks bad, they tend to go together or the surviving one has been running stressed and is on its way out anyway.

one thing i'd do before assuming its the finals though — check the driver stage too. on mine the problem ended up being a bad solder joint on one of the driver board connectors which was starving the PA of drive. took me forever to find because everything looked fine visually until i started poking around with a scope. classic intermittent cold joint thing.

had a 757GX years ago, fun radio. if its putting out evenly low across all bands that does point more to the PA than anything band-specific like a filter or LPF issue. discoloration on the transistor case is never a good sign, id pull it and check it out of circuit. just dont forget to check the bias pot while youre in there, sometimes they drift and thats all it takes to mess up the output.