Were it me i´d most certainly hand the unit the service it´s obviously crying for.
Have worked on the two basic versions of that amp on occasion and...they´re real high quality units. The echo/reverb in turn really sets it apart,and there´s two different versions of that too.
The early KV-40 and KV-50 were basically the same amp though,apart from the real early KV-40.
The real early KV-40 units share knobs with the stand alone reverb and earlier 35W PA amp. In other words simple to pinpoint.
They lack the later fabled reverb/echo units but on the other hand sport a motor driven tremolo.
The later KV-40´s and KV-50´s though are basically the same amplifier. It can be reasoned that there were deviations,and indeed. Some later 50 units lacked adjustable primary voltage for instance and were thus 220VAC units only. Something to keep in mind as you overhaul such units.
Then the fabled reverb unit. It IS a real gem it´s just that they are often broken and what mainly gives up in them,sorry to say,are the stock Bogen U-100 tapeheads. I searched long and hard for replacements and as it turns out you can revive these units by the use of the tapeheads for Klemt echoes. You just "undress" them from their shields and install them to the stock Schaller bases.
From the looks of it within my own KV-50 had seen an electrolyte explosion at some time. None the less the basic amplifier in itself it simple and easy to overhaul. It comes down to replacing components really.
Preamp box in turn is very much built in the same manner. Simple and to the point. The unit in these pictures is from 1966 by the way.
Atop that there´s the KV-50ST version which is a hyrbid amp but as you state this to be a KV-50 only i presume this amp of yours is the all tube version. The KV-50ST looks a little different but from a poweramp/PSU point of view is the same amp as the earlier KV-50 all tube versions.
What differs is their preamp and in turn the reverb,which is now more of a Binson setup copy.
