Fragile Items, such as a Cart’, not understood by a Cleaner, or any other individual who expresses an interest in it are now quite precarious, and exposed to detriment.
Fortunately there are options available to consider when the worse case happens.
VAS NY Inc has successfully rebuilt non-working Transfiguration Cartridges.
One UK Based Cart’ Owner, who sent a donor 'no longer made', Trans’n Proteus Cartridge to VAS was extremely impressed with the ’now working’ returned Cart’, they were very satisfied with the Overall Costs as well.
I have told a full story of this Cart’ Owners experience in another thread.
Investigating your options on a Third Party Service Rebuild, can’t do any harm, and the rebuild might just extend your experience with this Cart’ for a very fair outlay.