There are so many requests for advice on this machine - not just here but on TFG - Pete Bingham's agony column - etc.
It's a very very simple machine - and if you are a 60's kid like me and had a meccano set (I almost had a size 10 don't you know) - it's even simpler.
So - on delivery of your morso - new or old - take it apart - got a digital camera? 'course you have - so - take about 30 shots of each bit you take apart before you do so - just incase. Once you have a heap of nuts and bolts - you must have all the tools you'll ever require to fix most any problem.
(A few allen keys, sockets and an adjustable - maybe more stuff for fine tuning/lubrication)
Whang those fences waaaaaaaaaaaaaaaay out - get 'em out of the way altogether and mitre a frame without them - that screwed rod that connects the blade housing to the pedal mechanism? Take the nuts to one end of the thread - top or bottom.
See if you can find a very cheap pair of blades on ebay - cut some wide aluminium profiles with them - or otherwise abuse them.
Then cut a wide flat wooden batten with them and adjust your machine close to sanity by trial and error; work back to what you had to start, but adjusted to you; not someone else or a factory default (which should be pretty good for most!) Then change the blades for good ones - tweak the left fence.
There's no micro chips, no PCBs no wires even. Above all don't be scared of it - it thrives on abuse!