Selling my friends gear Looking for info

My friends' brother Bruce passed away unexpectedly in 2002. His music collection and gear was left at his mothers for 15yrs, which has been passed along to me to sell on his behalf. His mom did not keep any paperwork for the gear so I'm looking for information on it. His main analog equipment includes a Pierre Lurne Audiomeca J1 turntable with SME IV tonearm and an unknown phono cartridge with an "M" on the front, as well as Mark Levinson No.331 Dual Monaural Power amp. I understand these were offered through the now closed Madrigal Audio Labs. I'd like to track down any info I can about the sale/service of these products, to resell for his brother. Bruce lived in Northeast Ohio, I am not sure who the salesman would have been? The ML 331 works but there is a hum and may need the cap upgrade available for the 33x series amps.  Also, is there anyone still in the NE Ohio are that could review/service the amp and turntable if needed so that it can be sold? Thanks all have a  good weekend.