My very first job after graduating college was working with a PDP-8. At one point we had a hardware failure. We had a maintenance contract, so DEC sent out an engineer. After confirming the fault from the diagnostics I had run, he pulled a circuit board out, unsoldered a transistor, and soldered in a new one.

We also upgraded the hardware while I worked there. We doubled the memory from 4K words (6K bytes) to 8K words. The upgrade cost five thousand dollars.