I opened the meter of an Hallicrafters SX-117 to mechanically adjust the zero.
Once open, the meter appeared to be of the moving iron type, that is with no
moving coil. But I was surprised to see that that meter has no spiral torsion
springs either; I can only see a metal (?) dish mounted on the axis, part of
which lies inside a rather flat coil.

With no spring, I cannot understand what forces the needle to stay at zero scale
in absence of current. Therefore I cannot figure out what I should do to adjust
the zero.

The HT-44 as well as the EICO 723 use the same type of meter. Dumping is poor,
and the needle keeps banging for a while when you apply a DC current.

73

Tony I0JX