The original is gold plated hollow pipe boron with tiny nude microline stylus, i have a few samples of perfectly working at-ml180 and at-ml170. I also have a few broken samples of both, one of them
is here. I think the best option is Expert Stylus & Cartridge Co. service in UK, they are very good in communication and very well organized, reasonable prices (imo). Contact Email: info@expertstylus.co.uk
Here is the info i got from them:
"We shall need to carry out a detailed examination and assuming we find the cartridge repairable, our charges to carry out a complete overhaul to include materials as necessary and auditioning will be between £291.00 - £330.00. With the work carried out we aim to return the cartridge to as near new condition as possible. Should we find the cartridge in relatively good order, apart from a badly damaged cantilever or the stylus to be showing excessive wear, our chatges will vary between £120.00 - £180.00."
I use my AT-ML180 and AT-ML170 on Victor UA-7045, Lustre GST-801 and Reed 3P "12 Cocobolo.