If I remember correctly the owner’s manual for my ’67 had enough info for basic repairs and maintenance. I’m sure there was a good picture, and diagrams, of the fusebox and univolt converter.
In retrospect I wish I hadn’t left it in the trailer when I sold it.
I got a shop manual on CD from an eBay seller out of Canada for my ’72. Just checked his “store” and didn’t see anything that old. You might have better luck searching on your own.
If you can find an owner’s manual for a ‘66-68 you should be in pretty good shape to start.
Check you PM Mailbox. I left a message for you there.