They really don't look bad but it doesn't take much cross-conduction to cause heating.
This type of amp generally uses 10 ohm gate resistors. You have a couple of options, replace the gate resistors or the 640s with 640Ns. I think I'd start with the resistors.
This type of amp generally uses 10 ohm gate resistors. You have a couple of options, replace the gate resistors or the 640s with 640Ns. I think I'd start with the resistors.
I use it a lot. Just have to set your temp and air flow rate correctly. I don't want to take it out of the heat sink unless I have to. I do have some hot tweezers if I can get them in there.
I took it out of the heat sink and replaced the 22 ohm resistors with 10 ohm resistors. It is now pulling 3.1 amps with no load and no input. Amazing at the difference.
Are the 640s and the 640Ns running about the same temperature?
It takes only a few thousandths of a second of cross-conduction to cause excessive heating.
It takes only a few thousandths of a second of cross-conduction to cause excessive heating.
They are almost identical when checked with my thermal camera. I am going to put it back into the heat sink for further testing.