Sure sounds like Q3 is partially on or in trouble.
You MIGHT be able to check the junctions with your meter, but it is in circuit. You MIGHT find a big problem. Better to pull it out and check the junctions.
If you don't have a 2N3906, just about any silicon PNP in that class will work just fine. -2N4403, 2N2907, etc. Nothing special about it.
I'm sure I've got something ?in my stash someplace. I've got some stuff in storage. ?If you can't find one in your junkbox, let me know and I'll see if I can rustle up a few 3906 or 4403 units and drop them in the mail. Confirm on offlist if your QRZ address is good.
-HRS
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On Mar 7, 2024, at 11:15?AM, Jim Bennett / K7TXA via groups.io <w6jhb@...> wrote:
?OK - finally back to radio stuff - sorry for the delay.
Yes, Q3 is the 2N3906 and is installed per the silkscreen E/B/C holes. I re-soldered all three connections, just to be sure. Also, that R4 jumper reads just a tad under 3 volts when power is applied. Same voltage as at the base and collector of Q3.?
?Just taking a wild-ass guess here, but since the LED is lit, it is getting voltage and shouldn't be until the key is pressed OR if Q3 has given up the ghost. Yes?
?Perhaps replacing Q3 is worth a try - I'll see if there are any on Amazon that I can get without having to buy a bazillion of them.
--
K7TXA / Eagle, ID
