Steve has covered the subject very well.  The original tools that August Link sent me are shown at https://aafradio.org/garajmahal/ARC-5_connector_ring.htm - but their design suggests another way of approaching the problem.  Considering the threaded ring as dispensable given that Steve has those sizes, you'll need Channel Lock (or similar) pliers with a large internal circular radius like this:

Protect the aluminum chassis in a circle around the nut with some thin tape and clamp the pliers around the retainer ring, then tap the "blue"side with a small dead blow hammer while holding the head of the pliers firmly against the chassis.  That will break loose the corrosion that Steve mentioned, and allow you to spin the now externally damaged nut off.  I used that approach numerous times before the ARC tools came along, and it seems to work well if you are not heavy handed.  Gentle taps will eventually break the corrosion bond.

73,
Mike  KC4TOS

On 8/18/2025 9:47 PM, Steve Williams wrote:
I think you're dealing with 75 year old aluminum corrosion.  Acetone won't fix that. I have dealt with the same thing with no luck so far. If you dont have a special pair of exact fit pliers, you're pretty much screwed, unless someone else has a better solution. I do have the knurled rings for sale on ebay, but you'll need to come up with a way cut the old ring off. Very carefull die grinder work to cut the ring only may work. I also have some of the more common recepticales listed. I may have an odd receptacle in the junk box as well. You may only have to weaken the ring in order to remove it. If I have the receptacle, then you can cut through both and replace both.
Good luck.
Ebay user ID, kb4dmf
KC4WN, Steve

On Mon, Aug 18, 2025, 8:24 PM Matt P <[email protected]> wrote:
OK Gents,
I am absolutely stumped: what is the secret to removing the retainer rings on a plug on a FT-233-A single receiver rack? I am finally getting around to replacing J-24 and have soaked it with acetone to disolve the laquer that was applied to keep tge retainer ring in place, but still no joy in getting to even budge. Do I just need more acetone?
73
Matt
W2NS