Thermal stability of the SX-28A can be improved. So, if you like it, except
for that problem, get an old Handbook out and read the section on
temperature compensation. A frequency counter, hair dryer with nozzle to
direct the heat, a calculator and a handful of temperature compensating caps
can become a pleasant evening project.

The mechanical stability issue of the SX-100 involves mechanical analysis of
the mechanical assemblies of that receiver. There is no simple mechanical
change that will fix the problem perfectly, rather the scientific approach
would be incremental. Stiffening up one assembly may simply transfer the
torque somewhere else. The simplest approach may be to isolate the entire
receiver from outside influence. If no outside stress is allowed to
influence the radio, then the inherent weakness of the chassis is
irrelevant.

An old friend complained that if he picked up the SX-100 and dropped it 2",
it would do a major jump in frequency, whereas other receivers would not.
The cure is to not pick up and drop the SX-100. It is not the ideal mobile
receiver, nor one to be used for narrow band cw during an earthquake.

73, Colin K7FM