Hi! Rick Duncan 
The MV voltage is 25V at the input power of 25V.
The pins of SHx are opposite in forward operation and reverse operation but do not exceed 25V maximum.
This is the result of an oscilloscope.
In addition, the waveform of the SHx pin of the PCB is attached.
The third picture is a photograph of the SHx pin.
The two photographs are SH1 and SH2 waveforms.
Is the low pulse a brake / slow decay?