Having some weird issues with TH9000D Plus UHF models. First TH9000D I bought had no RX audio but would transmit fine (including with ASL3). The vendor was good enough to replace it even though the Amazon return period had passed. Got the replacement today and find that when I connect the RL20 to the TH9000, the display goes "blank" and I get nothing on RX or TX. If I disconnect the RL20, the TH9000 behaves as it should. I'm not certain, but I think maybe the interfact connector on the TH9000 PCB has been installed backwards because. I have a VHF TH9000D which works fine with ASL3, and I note that the PCB connector is installed in the other direction. Has anyone else had this problem. Yes, I could rewire everything but I would rather wait until I'm sure that is the actual problem.
Jeff, it certainly sounds like a wiring issue of some sort as it seems perhaps the cos/squelch line may have voltage it should not or be pulled to ground when it should not. Something along those lines.
I'm thinking along the same lines. What I might do is wire up a cable with DB9 connectors in sort of a cross-over fashion, once I figure out how it should be wired, and see if that works. If the interface connector inside the TH9000 is indeed installed backwards, it shouldn't too difficult at all to essentially just reverse the wiring.
Well, I always suggest using a buffer transistor in any case on logic.
I know everyone likes plug-n-play, but it just make sense when trouble shooting.
And circuit protection.
Perhaps you can publish the diagram for the plug and see if it is an obvious error one of us can pick up on.
So I contacted the vendor about this and sent photos. They agreed that the connector had been installed backwards and forwarded the problem to the QA department, which replied with instructions on how to “fix” the problem (using pliers to remove the connector and then reinsert it correctly). I assumed that they meant I would have to unsolder the connector; however, after they sent a video on how to do it, all that was necessary was to remove the housing (which is apparently held in only by the pins) from the pins and replace it in the correct orientation. Solved the problem.