Closer Look

I removed and threw away the four strings that were on the instrument, they were probably too worn to use anyway. Taking a closer look I noticed two of the brackets that hold the head (round bit in the middle) in place appeared to have been replaced with brackets from another instrument that didn't quite fit. The bottom two Z Brackets are the replaced ones. They're thicker than the other 6.

The pot (the bowl bit) was warped very badly. It looks like the strings had pulled the bottom of the pot inwards so it was no longer round. A common failure on cheaper old Zither Banjos and probably why they fell out of favour, I suspect the oversized Z brackets probably contributed to the warping too. Whoever installed them didn't actually screw one in place and the other has a random screw going into the pot at an odd angle. There's a metal bracket at the back to help maintain the curve against the pull of the strings but the pot had pulled away from that.

I was going to have to remove the head if I was going to do anything about the z brackets and warped pot. To do that you just undo the screws holding the brackets to the pot and pull it out. In theory. It turned out the head was well and truly jammed into the pot, probably because of the oversized z brackets and the pot being so badly warped. Eventually I got it out by prising the z brackets from the edge with a flat edge and when it was high enough levering it the rest of the way with a wide flat screwdriver.

The vellum (round circle of skin) was undamaged. But there was a dent in the edge of the tension ring, I don't think it'd effect the functionality in a big way and I'd guess it was caused buy either someone prising the  head out of the pot or by forcing the head into the pot with the two oversized brackets in place.

With a pair of pliers and a little force I was able to straighten up that edge.

The z brackets had left indentations in the sides of the pot. Not much I can do about those really but I suspect the head shouldn't be jammed in so tightly as the wooden pot is mean to resonate and this would reduce the volume. The screws holding the brackets weren't straight either so at some point I may need to do something to stabilise them a bit.

At some point one of the tensioners has been overtightened causing a chunk of metal to break off on the tone ring. In theory I could silver solder a piece of metal into there and rethread the hole but it could do more harm than good if it goes wrong and I think as it's held this long it'll probably be okay.

There was also a crack in the pot. I'd originally envisioned spending about a week on the instrument but evidently this is going to take a long time to sort out. It'd probably be more suited to hanging on a wall than restoration but I'll give it a try.