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  1. C

    Cobra 29 Constant Key Up

    Yeah! Thanks for the help. I appreciate it.
  2. C

    Cobra 29 Constant Key Up

    C121 :p
  3. C

    Cobra 29 Constant Key Up

    I’ll follow through with your suggestions. Last week I pulled the leg of every resistor in the red lines after your previous suggestions. I’ll get back to work on it thanks for the response.
  4. C

    Cobra 29 Constant Key Up

    I don’t know how to simulate RX mode when the whole problem is that it is stuck on tx. Let me know and I can report back. TX Mode Voltages: 2.6/1.9./1.1/2.6/0.0/7.6/2.1/5.0/7.7 Note: When I lift the legs to L21 - which are on the same trace as ic3 pin 6 - pin 6 goes to 0.6v it will unkey...
  5. C

    Cobra 29 Constant Key Up

    I’ve been out of town. Hopefully, I can have this done before I leave again. Fortunately, it’s not time sensitive. Removed R70. No change. Will continue w/ your additional instructions….
  6. C

    Cobra 29 Constant Key Up

    Thanks for that info LC. I’ll check it out and post the findings.
  7. C

    Cobra 29 Constant Key Up

    I can do that when I get back but the transistor works. I swapped it with another radio with no change. The other radio works fine with the transistor from the nonworking radio. I can’t recall those voltages off the top of my head but I believe the trace for the collector, middle leg, was...
  8. C

    Cobra 29 Constant Key Up

    Thanks for that. And FYI all 3 legs of TR21 are w/in .1v of 8 volts at all times.
  9. C

    Cobra 29 Constant Key Up

    NZ8n Everything back to stock: Radios stays keyed up. Red TX light is on. R95 lifted: Radio unkeys (no rf power output) but red TX light still stays on.
  10. C

    Cobra 29 Constant Key Up

    Sorry, I failed to mention, I replaced it.
  11. C

    Cobra 29 Constant Key Up

    Thanks. I replaced c117 w/ new. TR21 still receiving ~8vdc Thanks Nomad. Middle leg is receiving 8 volts. Desoldering center leg unkeys radio. Trying to trace down the short. Thanks Nomad. Middle leg is receiving 8 volts. Desoldering center leg unkeys radio. Trying to trace down the short...
  12. C

    Cobra 29 Constant Key Up

    Update: I was in the correct area yesterday as I was trying to trace down the issue. TR21 has 7.24/7.93/8.05 volts to each leg. Unsoldering center leg unkeys the radio. Today: Replaced C117 w/ new and no change. Lifting r95 also unkeys radio.
  13. C

    Cobra 29 Constant Key Up

    Thanks. I’ll be checking all these things the first chance I get today. Will let y’all know.
  14. C

    Cobra 29 Constant Key Up

    I’ll get back at it tomorrow.
  15. C

    Cobra 29 Constant Key Up

    I believe this is the schematic https://web.archive.org/web/20190712225721/http://www.cbtricks.com/radios/cobra/29ltd_chr/graphics/cobra_29ltd_chr_sch.pdf
  16. C

    Cobra 29 Constant Key Up

    It’s pretty much a new radio. Cobra 29 Chrome.
  17. C

    Cobra 29 Constant Key Up

    Which one is that?
  18. C

    Cobra 29 Constant Key Up

    Radio keys up constantly (with or without a microphone). Besides that, everything works. A quick check of PTT pin 3 does NOT show a short to ground. What info can I provide for further help?
  19. C

    Galaxy DX2547 No Receive Audio - GNF affect

    Well, that was easy. J413 was plugged in backwards. The nf board was only receiving power when the galaxy noise filter button was pressed. Thanks alot guys.
  20. C

    Galaxy DX2547 No Receive Audio - GNF affect

    Finally had a little time to check this out. The new part did not resolve the issue so I need to start checking voltages etc. will update.
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