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New TinyTrak3+ stuck in transmit.

Bill WA4OPQ All Messages By This Member #927 I finished assembling my first TinyTrak3+ yesterday and the radio cable arrived today. When I hooked it up (GPS hasn't arrived yet) it powered up OK, but it was stuck in transmit. If I checked "No Tx While PTT In" in the config, and then the stuck xmtr problem went away, but it would never transmit. It looked like U1 pin 11 was stuck low, but even removing D5 didn't help. Finally, I removed U1 and found pin 11 still low. Really? Eventually I loosened U2 and the short went away. I couldn't see exactly what caused the short, I'll chalk it up to a micro-meteorite. But until I get a TO-220 insulator it's going to remain lifted up a bit.? This has probably been answered before on the old message board, I'm new here and had little to search. So I'm posting this for some poor soul in the future.?
Rob Giuliano All Messages By This Member #928 I am baffled by the voltage regulator being the issue.? Did you double check the soldering around it? The PPT circuit has a few connections that could cause the PTT to be active. With U2 fully in place and the radio in TX, is the PTT LED on or is the radio in TX without the LED on? (J4 must be in place). ?? If not, then verify Q1 orientation. Moving to the pin 11, this is the feedback for PTT IN and should NOT control the PTT unless there is something ????? wrong with D5 and D6.? In this case check D5 and D6 orientation.? ???? If you remove both, does the problem go away?? Robert Giuliano KB8RCO On Sunday, April 18, 2021, 2:34:04 AM EDT, Bill WA4OPQ <wa4opq@...> wrote: I finished assembling my first TinyTrak3+ yesterday and the radio cable arrived today. When I hooked it up (GPS hasn't arrived yet) it powered up OK, but it was stuck in transmit. If I checked "No Tx While PTT In" in the config, and then the stuck xmtr problem went away, but it would never transmit. It looked like U1 pin 11 was stuck low, but even removing D5 didn't help. Finally, I removed U1 and found pin 11 still low. Really? Eventually I loosened U2 and the short went away. I couldn't see exactly what caused the short, I'll chalk it up to a micro-meteorite. But until I get a TO-220 insulator it's going to remain lifted up a bit.? This has probably been answered before on the old message board, I'm new here and had little to search. So I'm posting this for some poor soul in the future.?
Bill WA4OPQ All Messages By This Member #930 Yes, I'm a bit baffled too. Yes I checked all the soldering. Orientation of D5 and D6 was correct. With "No TX on PTT In" unchecked it caused the radio to transmit and the red LED came on. As soon as I wrote the config with "No TX on PTT in"? the red LED extinguished and the radio unkeyed. While in this mode it would not send regular messages or bulletins, but if I had it send audio tones that function worked correctly. That tells me the PTT circuit is working correctly. With D5 removed and U1 removed pin 11 was still shorted. The only thing then connected to pin 11 was the trace going to D5, which goes under U2. The only explanation that makes any sense is that there was a small bump on the trace that pierced the solder mask and it touched the grounded back of U2.? I'll go back and look at that trace with a fine tooth comb; at the time I was a bit frazzled and didn't do it.
Bill WA4OPQ All Messages By This Member #932 Mystery solved... It appears that on the latest batch of boards (mine, at least) the large hole in the center of the board has shifted so that the trace that goes from U1 pin 11 to D5 is shorted to the large plated through hole. (see arrow for location). This connects the large ground plane area on the other side to pin 11 also, so when the screw and nut are installed on U2 it grounds pin 11 and creates the stuck PTT that I experienced. So U2 will remain floating above the board and all is good.
Rob Giuliano All Messages By This Member #933 Have you considered a piece of insulation under U2 such that it covers the trace that us being shorted? toggle quoted message Show quoted text On Mon, Apr 19, 2021 at 21:29, Bill WA4OPQ <wa4opq@...> wrote: Mystery solved... It appears that on the latest batch of boards (mine, at least) the large hole in the center of the board has shifted so that the trace that goes from U1 pin 11 to D5 is shorted to the large plated through hole. (see arrow for location). This connects the large ground plane area on the other side to pin 11 also, so when the screw and nut are installed on U2 it grounds pin 11 and creates the stuck PTT that I experienced. So U2 will remain floating above the board and all is good.
Bill WA4OPQ All Messages By This Member #934 Yes, I found a mica TO-220 insulator, which did not work. It's the U2 mounting screw that is completing the circuit. I'll dig around for a plastic screw and nut set next.

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