[Penthode]

I considered a chemical de-ruster. However I have had good results using electrolysis. It is cheaper too.

With the chassis half stripped off, the chassis was immersed up to that point. The chassis is the cathode (-) and the carbon slab the anode (+). 5 Amperes for two hours.

Removed the chassis and lightly went over the derusted section with a rotary dremel brush and 0000 steel wool. Most of the cadmium plating remained: all on the top and about 80% on the bottom. I will apply some zinc paint over the affected areas to prevent it from rusting. The poor CT-100 looks like it had a tough early life and I intend keeping it in a climate controlled environment.

I have a lot of cleaning ahead. I want to first clean off the top of the rest of the chassis then proceed with reassembly. I will re-rivet the tube sockets and tag strips as original. Note the tubular rivets are available on eBay for abut $9 for 200 and free shipping from China! The IF tube sockets with shield clamp require 3/32"D x 7/32"L , the non-shielded tubes 3/32"D x 5/32"L and the tag strips 1/8"D x 1/8"L.