Your car should have a circuit which measures the RPM of the compressor and compares it to engine RPM. If it detectes the compressor locking up, it should cut out the compressor. The Klima relay performs this function. It must be either broken or bypassed on your car. It's a pain in the butt because 99% of the time it triggers it's a false alarm, but it's dang nice to have when you need it. I had my compressor lock up in the middle of the west Texas desert. It was a warm drive home, but the cutout function worked like a charm, so I drove rather than walked...
I picked up a junkyard (er, recycled...) compressor for my '87 300TDT. It came off a 190D of about the same year. It seems many MBs from the mid 80s used the 10P15C.
Later cars switched to the 10P17, which is not interchangable. I don't know whether the early 90s diesels used this compressor or not. If they did, it might be possible to change over. Of course, you'd have to find the correct mounting brackets and such.