A few mechanical things.
I like to clean the rear cams with some solvent and a Qtip, then I re-lube with silicone grease. Never gums and lasts forever, thin shmeer is all you need.
I also cleaned and lubed, gently all the sliding metal on metal parts
I relube all the rotating shaft bearings with 100 grade silicone oil, from the hobby shop that sells the stuff in 3oz bottles for RC cars shocks!
Especially lube the ant trimmer shaft!
Mine is smooth as silk now when you move a knob.
Soft tubes will cause low sensitivity. I just got a second R-388 and it had a soft tube in the IF, and was fairly deaf as a result.
Afaik, the 51J-3 and the R-388 are identical.
Watch out for the main plug in power supply cap - it can become leaky and make ur power transformer run very hot. I rebuilt mine with an octal plug, some aluminum tubing and filled it with modern caps and silicone rubber, put a cap on the end.
Fwiw, I use a dow-key type relay with a Valiant II (3 x 6146) running about 75w of carrier, and I do not mute the receiver, the isolation of the dow-key is sufficient to put the signal into the receiver at about 20dB over S9 (not that the meter shows an S9) and I simply use it for monitoring as I speak... I do have the speaker at sufficient distance and placement (and phase - it matters) so as to not feed back. FYI.
I think the 51J-2 is slightly different inside...
I'm very happy with mine on AM. Use it all the time.
Considered a product detector mod, but never pulled the trigger. Think I'd try the 7360 tube first. There is a plug-in solid state thing being sold online. There are numerous other product detector mods in the mags from back in the day. Of course they switch in and out...
Totally classic receiver, top of the food chain!
_-_-bear
the image is the one I just got, as it sits... love to see a pic of yours!
