Thanks, Ken. You are right, the smallest of details can really have huge effects. There was a bow in the body that measured approximately 5/16" off level on each end of the dulcimer. All of that from a 2mm extra rise in one side panel. After I thought about it, it made perfect sense. So, now the fun begins.

I look forward to the photos. It sounds like an interesting project. It is amazing how a one little irregularity in a side can throw the whole instrument out of whack. It takes creative thinking to correct some of them.

Ken

"The dulcimer sings a sweet song."

Problem solved (by accident)!

This morning, I folded a piece of cloth and placed it under the center of the dulcimer, and using soft wood blocks, clamped the dulcimer on each end to my work bench. I was hoping that by putting it under some pressure, it would slowly begin to flatten out. I know, I know, this is not a common or excepted woodworking process for a musical instrument and a seasoned woodworker. I know better. I  just get a wild hair every once in a while. While exiting my shop, I heard a large pop, went back and saw that one side of the dulcimer had blown out. Had it under a lot more pressure than thought. Anyway, l unclamped it, and was surprised to see that the bend in the dulcimer was almost completely gone. Also noticed that the blown out side seemed to be a little taller than the opposite side. Measured and saw the blown out side piece was 2mm taller toward the middle. That would explain the eventual warping of the body and fret board and also the slight twisting. 

I now plan to carefully trim the excess material from the high side piece and reglue it, then continue the restoration. 

I received this as a kit when I was a teenager about 50 some years ago, and had no real woodworking or finishing skills. It looks pretty rough. Now that I'm retired, I though it would be nice to restore it and get it singing again. Going to fabricate a new maple fret board. Ordered new fret wire and strings. Looking forward to bringing it back to life. 

When completed, I'll post some pics.

Can you provide pictures?

Does anyone have any ideas in how to fix a warped dulcimer? It has a concave bend in it. Attempting to take the bend out of the body of an old teardrop kit dulcimer. I was able to remove the fret board that was warped as well, and now wanting to somehow flatten the instrument out. If successful,  I'll  install  a new fret board and continue refurbishing it.