Hi there I have just bought a cheap but hardly used SIP Migmate 130. Reviewed as best in Practical Classics, but dismayed to see it rubbished in this forum!! The wire feed does not appear to work properly and does not appear to push the wire through. I can pull gently on the wire and it feeds with the motor going. However,it almost feels as though there is a regular tight spot as it is pulled. The wire is slighly rusty which I know will not help. Any ideas please?