An absolute rock and roll classic. This Marshall JMP50 model 1987 from 1973 recently received routine maintenance and is in great condition. It retains the original transformers and most of its desirable mustard caps. Changes include a handful of out of spec capacitors and resistors, the two volume knobs, tubes, and most likely the rear panel screws. A grounded 3 prong plug was also added. The chassis is held in place with hex bolts screwed into press in nuts in the bottom of the cabinet. It actually makes removing the chassis much easier than the traditional nut and bolt setup. The handle is missing one of the covers. 

It sounds just like a vintage 50 watt Marshall should. Channel I is bright and cutting while channel II is warmer and more mellow. Jumpering the channels provides the best of both worlds with the ability to dial in just the right amount of bite and low end.