the IC-751a
I'm fairly certain... well, 98% certain, anyway ...that I know what's wrong with my old IC-751a...
Assuming all of my testing and the initial release of blue smoke back in 2003 or 4 (whenever it was) hasn't hurt the actual PA components, and assuming I'm not missing something (which is entirely possible!), I believe the problem is in the TX/RX switching board attached to the SO-239.
I've found a complete "back end" for an IC-751 (non -a) on eBay that wasn't god-awful expensive, and I've ordered it to have on hand for parts.
IF the two are identical (I'm not sure if they are or aren't...) I may just swap them out, as this back end is supposed to be fully operational... if they're not identical, I'll have to mine parts from one to fix the other.
Why is all of this important to me?
I miss that radio. It was the first NICE radio I ever bought for myself. Even though it was 20-ish years old when I got it, it still had the best receiver I've ever heard, bar none. As much as I love the IC-7610 I'm using now, the receiver just doesn't have the same "quality" to it. When I say "quality" I'm referring to its characteristics and not its components. The way it was both sensitive AND selective... it was just pleasant on the ear.
The 7610 is outstanding, don't get me wrong... Its pure DSP receiver can be as selective as you want, and it'll always be as sensitive as a wide-open DSP receiver that works on the raw signal can be. DSP allows me to configure my own filters on the fly, too, so filtering out all the other CW signals in a crowded band to isolate the one signal I want is quite easy - and not possible on the all-analog IC-751a...
Yet, somehow, the receiver on the IC-751a is more pleasant to the ear.
Maybe it's nostalgia... the remembrance of when I was much newer at the hobby, and everything was shiny and exciting.
Maybe it's that I'm much better at picking out which CW signal I want to work in a crowded band - a skill that only arises from experience.
Maybe it's that my ears are getting older.
Whatever it is, I look forward to putting the old girl back on the air, especially now that I've got the room for it.