Quote:
Originally Posted by GBBR
I understand that it may have been just a small blow resistor or something like that but I know nobody willing to bother daignosing it, or fixing a circuit like that. I'm ageist the diag, labpur, and parts may rack up to a price higher that the spectre.
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Well, the MOSFET is actually the most probable part to blow.
It "should" be the largest chip with only 3 tab (probably the middle one cut and not connected, as the back/heatsink is also connected to that).
It might however be a SO8-type chip (smallish, with 8 pins, 4 on each side). In that case, I would not be surprised it blown. Without active cooling (read a 1"x1" aluminum heatsink and a fan), it can't take over 10A really well.
What gen is the ASCU you have?
The pics I can find of gen3+ have the FETS (D2PAK) mounted on the same board as the trigger parts, and earlier have an external "power" module, probably housing the FETs.
On GEN3+, there does not seem to be any protection diode (other than the one built-into the FET chip). And there is not much space to add one in fact.
You could probably fit it here where they say to add tape, but you would need to dremel every rib in the mechbox side to clear some space (a decent diode is the same thickness as the FET chip).
As you can see, the metal tabs on the back of the FET are used to connect the drain/source (depending on the specs) with a larger connection and also dissipate the heat through the surface (and wires as they are connected there). If theses are not making a very good contact with the mechbox shell side, they will overheat and blow.
Sending you a PM.