CHECK my email, it is nando37
The problem to suggest what to test, makes it very difficult, if we do not have a topography of the board to give you a road test sequence.
Also, the need to have and to understand a lot of electronics to be able to solve certain conditions that have to be recognized as a result of a measurement or a signal injection or even the presence of a voltage range.
Basically, it is a DC/DC transformer at high frequency, let's say 30 to 50 KHz and the transformer has, normally two outputs, one Positive, and one Negative up to the peak voltage of the 60 or 50 Hz value plus a switch to present to the output either the positive or the negative voltages and some additional circuit to cut off the output pulses for a certain time of the MSW wave form, basically the pulses are around 90 degrees wide, for each pulse, and the rest of the time the additional circuit cuts the output for, about 90 degrees between each alternating polarity pulses.
The high frequency transformer has the output with a full wave rectifier with transformer center, so this way a positive and a negative voltages are generated, as indicated previously, to present a continuous voltage level with a very small transformer and high power output.
Some converters have a single output winding that is floating and the additional circuitry grounds alternating polarities to generate the MSW wave form.
Some of the DC/AC converters have some excellent circuit protection,
Regards
Nando
