This afternoon was spent finishing the clean up of the three PA LOADING Coils. In the process of doing this, I noticed I had also not cleaned the greasy soot from the inside faces of the ¼-inch thick brown phenolic resin boards the three coils are mounted on. This in turn, also drew much closer attention to component S17A, which is also mounted to the rear board immediately to the left of the large upper PA LOADING Coil. This is the very important Relay Switch that disconnects the Receiver from the Aerial Circuits whenever the 52-Set goes into transmit mode.
I has noticed the S17A Relay Switch many times but assumed it to be of a metal box construction. It was only now that I finally realized that it was built around three large, white ceramic insulating plates, and these has gone grey-brown with the crude I was needing to clean up.
I started by sliding three layers of paper towel underneath the three coil assemblies and above the large metal tuning condenser at the bottom of the chassis, in order to catch any drips. I then sprayed everything that needed cleaning, with my trusty solvent.
Earlier, I had found a section from an old flannel sheet and a set of my wife’s pinking shears. The latter are used to cut fabric in a triangle saw tooth pattern, rather than a straight line. This stops the fabric from fraying and shedding bits all over the place. I made several 2-inch wide, three foot long strips and by looping them carefully around each coil was able to hold each end and pull it gently back and forth along each coil, cleaning off all the soot the solvent had lifted free, Then a few puffs of 30 lb. air from the compressor to dry the coils off and I was done.
I was able to get other strips of the flannel up against the inner faces of the front and rear brown phenolic boards, rather like dental floss and clean them up as well.
For the S17A Relay, out came the Q-Tips once more and about a dozen were used with the solvent to clean up all the crud on the ceramic insulating plates. And out popped the CMC Part Number on the bottom plate.
When I removed the layers of paper towel when finished, they were soaked and varied in colour from pale amber to grey-black. Wiped up the lower edges of the boards with another towel and I was done.
David
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