Re: 2N2222A getting super hot

Gordon Gibby <ggibby@...>

Maybe check with an ohmmeter to make sure you ended up with 11 ohms. Then measure the voltage across the resistors while turned on, use ohms law to figure out the current through the transistors

Allyson told people what current she preferred.

Measure the voltage from the emitter to the collector, multiply by the current through the transistor, to figure out the resting dissipation; compared to the specified for the device.

Somewhere in there you’ll probably find your problem. There might be an incorrect biasing set up.


On Mar 29, 2019, at 02:44, Joe Puma <@kd2nfc> wrote:


I performed Alison's mod and replaced the 3904’s with 2N2222A T08. I also paralleled the 22 ohm resistors to get the 11 ohms. Not to mention I changed q90 and replaced the resister with 2.55kohms. The 2n2222a’s that have their resistors lowered to 11 ohms get really hot. the other set of drivers that don’t have their resistors lowered ( im not sure why) dont get that hot but they get warm.

when testing amp draw from brown wire in line with amp meter and rv2 and 3 fully clockwise I get 0amp on key up. I turn up one 100ma, then the other. now im at 200ma. If I talk in the mic It swings to 400ma+. With CW key down it jumps to under 1amp.

I am on a dummy load

I dont have a power meter.

Does this make sense after doing that mod. is there a reason why those 2n2222a are getting so hot, can i bring RV1 and 2 up so its drawing more current?


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