I have finally disassembled my sBitx fully and removed final MOSFETs.? I have to cut the away to not damage the PCB. One of the was still alive (so I'll probably use it for prototyping):
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But the second is broken (probably due to overheating):
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So it looks like a fan is the "must have" if one wants longer continuously work in digital modes.
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Now I have to decide if I should mount the new MOSFETs and reassemble the device as it is, or wait until the new aluminum-nitrid isolators arrive.
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I'm also afraid about the PCB state when replacement of finals may repeate multiple times. It seems that the pads of Q16 and Q17 are quite delicate. If they are gradually damage during replacements, at ID reaching 4 A (or even more in a pulse) the PCB may gradually deteriorate and finally fail.
