KJINTF many thanks for the pointers on converter. I googled for diagrams and parts but was unable to come with anything. I just noticed a chip inside top of cover with heat shrink on lead but for the life of me I cannot find or figure out where it was connected.Have done quite a bit of electronic work over the years but have done very little in the last few years. Again many thanks for the reply and pointers. I'll have to see if I can dig out and dust off some old test equipment I used to have lying around if it still works.