[Boatanchors] Interesting AR-88 Issue

[Rodger]

Over the last couple of days I started working on an RCA AR-88 that I 
picked up earlier this summer.  Although it looked fairly good it needed 
cleaning and it was sporting an SX-42 S meter instead of anything close 
to the original RCA look.  Once I started working on it I also found 
several of the "bathtub" caps were leaking oil from their seals so I 
replaced all of them.  Upon power up there was no smoke and good results 
except on the two highest ranges and a quick check showed the HFO wasn't 
working on these two ranges.  A few measurements with the ohmmeter 
indicated an interesting reading because it appeared that a large 
capacitor was slowly being charged on these ranges between the coil 
terminals and ground but the oscillator coils are isolated from the rest 
of the circuit by fairly small capacitors so that made no sense.  The 
tubular trimmer capacitors themselves were the problem.  On the AR-88 
the trimmer capacitors are composed of an aluminum tube with a solid 
aluminum bar inside insulated by a ceramic disc and whatever cleaner or 
lubricant that was used by the previous owner got inside the caps on 
these two ranges and turned them into some sort of home made 
electrolytic cap, when I took them apart I found a white pasty substance 
inside.  I didn't bother to measure the capacitance before cleaning them 
up but fortunately a quick disassembly and cleaning restored them to 
normal operation and now the AR-88 is working properly on all ranges.  I 
checked the other trimmer caps in the oscillator section and they were 
fine so apparently only the two highest range caps were attacked by 
cleaning/lubricant guy.

This ends this breaking news story and now back to your regularly 
scheduled program,  "Upgrade Controversy"  :)

Rodger WQ9E