So, the dissipation will be quite high here also. That equates to lots of watts in dissipation each time the lamp turns on.Īt the low signal voltage out of the MCU the device will be marginal to turn on fully when the lamp is on. If you are unsure how to disassemble your Saturn, I made a guide recently for my Silencer kits.Īlthough the datasheet shows 40A, 60V capability for the MOSFET that is only true for a large Vgs voltage.Īt turn on the large surge of current that charges the 470uF capacitor will mean the MOSFET is operating in its linear region – it will have significant volts across it whilst passing the charging current. Maybe we can find the problem or rule them out as the root of the problem. If you are an owner of a newer Saturn that has all three boost-converters on a single board and you are not afraid to disassemble your Saturn, please, get in touch with me and send me detailed pictures of the new boost converters. Or there is simply a bad batch of the MOSFETs.However, as I don’t have this design available, I cannot tell. Therefore, there could be a flaw in the design that kills the transistors. Elegoo changed their boost converters design for the newer Saturns.However, the problem appeared only recently therefore it affects only new Saturns (mine is from the first preorder batch). There seems to be nothing that could kill the transistor. I also took my Saturn and examined the input of the boost converters with osciloscope. On top of that, there is a big capacitor on the input of the boost converter, that should act as a snubber for such pulses. Also, the MOSFET seems to be sufficiently rated according to the datasheet. However, there is diode protection for this. The first suspect is that the boost converter is an induction load that can create high-voltage spikes across the inputs that can easily kill the MOSFET. The fix is easy, but it would be nice to find the cause. This is why I replaced it with a piece of wire.Īfter swapping the transistors, the board works again! Why does it happen? Note that I wasn’t carefull and I broke the gate trace. The middle transistor is not used for anything, therefore, we can desolder it and solder it instead of the broken transistor. Luckily, the manufacturer gave us a spare transitor. I have also confirmed this after removing the transistor. It is shot-throught and it is always conductive. After measuring the transistor the problem is clear – the transistor is dead.
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