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If you have a current limited supply at about 2Amps OR? a variable voltage supply, Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye. I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios. Alternatively, I have a MFJ power supply that is adjustable.? ?? With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was damaged BEFORE CONNECTING ANY RASPBERY?TO IT. If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else see which ones are getting HOT.? ?? On Amazon, there are multiple sources for 2219a's and they aren't that expensive..... One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired. Let usknow?how it goes! Gordon KX4Z On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via <mikebales73=[email protected]> wrote:
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