Elna Lotus 36 bobbin problem?

The bobbin under the needles became tangled up and after the cotton was pulled out with some force the needle no longer picks up the bobbin thread. Nothing appears to be bent or broken including the timing belt. I am told this may be a timing problem. Is this something that can be fixed on a DIY basis by a reasonably competent individual or will it require an engineer? Is a service manual for this machine available? A google search has not been fruitful.