XIEGU XPA125B + EXTTR mosfet blown

[Max]

Hi, 

before I found this forum, I did exctly what Heath Petty wrote here and connected the link between PPT for Xiegu and EXTTR the wrong way. https://groups.google.com/g/hermes-lite/c/gBU_Wjh-5Uk/m/RR_O87_ZAgAJ

Yes, I am aware I messed up. So let's talk about fixing things. The Hermes seems to work fine, everything works, just EXTTR seems dead. If I connect Xiegu, it remains in TX mode, so the pin is constantly pulled. Measuring at TP4 (FPGA out to the little transistor) I always measure 1.9V.

I replaced the Q5. I replaced R125 (only had 10k but I think should be fine). But the FPGA seems not to move the pin at all. Any more ideas? Any hacky way to get around? I am not into Verilog, somewhere it was mentioned to change the pint, but I would need a guide for that. Maybe there is a simpler way?

Thanks a lot for any hint!

Best regards

Max

[Jirka Culak]

Thats sad. You blew the FPGA.

I had the same experience. Maybe possible future mod to add a TVS Diode or 1n4148 in path of TX PIN of FPGA.

I tried to replace FPGA (HOT AIR) but failed, so ended up with three dead HL2s a ordere new one (lucky the cost is reasonable still!).

73 Jiri OK2IT

PS - From now on I use EXTR into small 5V DC Relay. That way it switches whatver I conenct.

Dne pátek 8. května 2026 v 15:02:25 UTC+2 uživatel Max napsal:

[Luca EA8DJR]

Just THAT pin of FPGA, don't need to change it but use a specific gateware that uses a free  pin for that function.

There are some post recently here in the group.

73

Luca