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Thanks for the advice. Here's what I have done so far. 1. Replaced the LM117 2. J5- 3v and 5V on their pins 3. 5v on TP1 4. 3.3v on TP2 5. 12v on Fan port 6. Replace the pin connector for the teensy

1) I would take out the teensy (socketed ? and possible?) and would check the TP?s like Oliver 2) if it?s ok 4 possibilities a) Teensy is defekt b) check Teensy Pin 46 (without Teensy) is there a

Here's the gain of my K9HZ 20W PA: If we calculate the gap between the feedback amplitude and the amplifier gain, we can quantify how much margin we have before the radio begins to oscillate. It's a

I had a Teensy blow when on power up because a the LM1117 failed. I replace the LM1117 with MP2307 buck converter module. The LM1117 had the fan and heatsink on it but its current rating is

Good detective work. That should do it. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator

I have now confirmed that, after I replaced U8, the latest version of the code (Ver66-9) on GitHub ( https://github.com/KI3P/SDTVer066-9 ) does not suffer from oscillations on any band with my V12

Also don't forget you have to slice the trace on the Teensy to disconnect the USB power. -- 73 Greg KF5N

Do you know how your Teensy got blown? That shouldn't happen. Before placing your Teensy on the board, power it up and check that the DC voltages are correct. The schematic is here:

I discovered that U8 (an RF switch) was not working on my LPF board. It provided very little isolation. I measured this by removing the LPF control board from my radio and testing it a NanoVNA and the

Great Terrance, thanks for the post. I hope others results will be good too. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC

I can report success with Bill's display driver board and also a caution.? I accidentally connected the display driver board to the Main board offset by one row and blew the MISO line.? Bodging that

I have a major problem with the main board. I built it with the reverse power protection. When I first built it I had 3.3vand5v at the test points. Now when I added the teensy and audio hat and test

Interesting, Jerry. If you have time, could you measure isolation from J8 to J7 with key down in CW, and PTT engaged in SSB, with your current SW version? dave

Mine is oscillating too. But only with the later software. - Jerry

Schematic and BOM on the GITHUB Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand

I completed my RF board last fall based upon the BOM "T41_RF_Board_BOM_V012.6_02-25-24.xlsx".? My RF board seems to work OK although "how well" is still a question.? I have not followed properly the

Today, I checked v50.2 and v66.4 after putting my T41's back together. ? Both versions have a 33-45MHz oscillation at the higher bands.? I have pretty low isolation PA Out to PA In at those

This should have arrived sometime today… Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator

Another way to test this is to disconnect the display altogether.? This can't be done with the existing software as the code will hang trying to start the RA8875 object.? However, in developing the

This is an edited version of the report to exhibit the effect on isolation of moving some tracks off of the LPF-Control board. Tomorrow, I will put the amplifier back in the circuit I have had an