On Thu, 03 Jan 2013 20:18:17 -0000, "Albert" <aodiversen@...>
wrote:
Could it be that after your modification the switching transistors get hotter? At first sight it is a trade-off between saturation voltage of the switching transistors and voltage across the FET. The sum of these voltages must remain more or less the same, in order to have the same voltage swing at the primaries of the inverter power transformer.
I only have experience with 7000 SPMSs. Good to know that these "modern" supplies are so different, in case my 2232 breaks down...
Isn't the 2246 inverter design just another variation of the saturable
core oscillator with T2205 designed to saturate before T2204? I see
the same configuration in the "good" 22xx series (2230 and 2232) but
the "evil" 22xx units (2225) use a completely different fixed
frequency push-pull stage based on the TL594. I suspect one of its
advantages is that the soft switching makes for less noise but I
suspect saturation causes more interference from magnetic flux
leakage. Maybe the later is why they went to a two transformer
design.
Tektronix used that saturable core oscillator technique a lot in their
high voltage inverters and I thought I remembered seeing it in some of
the 7000 series.
David Hess