good, I get the general idea from the Readers Digest reprint. Now it looks like I will need a spanner screwdriver to loosen the lock nut. Appears to be about a 4mm +or- gap over the adjusting screw. Anyone able to tell me what the size is  (is there a German standard), or where is a good source for a set of tools in that approximate range?

I have a standard plywood case with a defective latch. Is there a source for replacements? I could try out something from Amazon under the category of Suitcase, or Musical instrument latches, I suppose.

I finally took the underwood to Berkeley Typewriter. A professional cleaning seems to have done the job.
Bill didn't mention any further repairs needed.

I can't say i feel a significant increase in the tension as it nears the left margin, but there is a fairly good pull from the spring. I tightened an extra turn (makes 6 and is near the limit). But that makes no difference at all. The keys and space bar seem (?) disconnected to any advancing mechanism. 

I just bought an Underwood 150 from an eBay seller. It was said to be in working order before sending. It arrived with no evident damage except that the draw band was disconnected. Now I've put it back on, and the main spring feels strong enough, yet the carriage doesn't advance. What can I try next?