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  1. T

    Cobra 29 High Power mod with 2sc1969 transistor

    well, I have reinstalled everything from the factory, and I have done a test. instead of the 2sc2078 I have placed a good 2sc1969. The final power has been 3.8w again. Either a component or setting fails before 2sc2314, or something discharges power to ground after 2sc1969. I comment on...
  2. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Wow, I'm not getting anything. I think the time has come to assume that this is beyond me, and I must reinstall the original components. I'll keep this souvenir kit, and use the Superstar 3900. This also implies that I appreciate all the help, I have learned things that I did not know. It is...
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    Cobra 29 High Power mod with 2sc1969 transistor

    Huff! I have read it 3 times but I am not able to understand what to do, my English is not good enough. Could you please do a little schematic of everything that I should add and where? Sorry to give you so much work. P.S. I guess the 2SC2314s I bought are fakes, because none of them give...
  4. T

    Cobra 29 High Power mod with 2sc1969 transistor

    I have put the original 2sc2314 and the 3.8w is back. I have measured the DC voltage after D11 and is 13.5v. in TX is 11.8v. I attach a full resolution Schematic.
  5. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Thanks for answering. My Dragon does have the transformer installed, you can see it in this photo: But if you look closely, I do not have the IC that is to the left of the TDA, like in your photo, the one that is bolted to the chassis. Measuring the voltage at some point on the transformer...
  6. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Okay I'll give it a try, but remember when I removed that coil, first try, I got 0W power. Only when I put it back on did I get some power.
  7. T

    Cobra 29 High Power mod with 2sc1969 transistor

    I must be the most unlucky person right now. today I received the 2sc2314. hfE of 334, good point. I install it on the radio without changing anything else since the last time and 0W and a voltage of 0.6v.
  8. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Agree. So do you think that with this scheme you will be able to propose another combination? I give you the time you need, maybe better wait for the 2SC2314 I bought to arrive (I don't know if they also make fakes of these), and then apply more changes? That 3.8W barrier is very strange.
  9. T

    Cobra 29 High Power mod with 2sc1969 transistor

    I think there is something wrong with the transmitter. RFC4 is out. I have used 3.9k in R1, and in R2 I have placed 710R together with a 1k pot in parallel, to be able to adjust that resistance. With values of R2 that are close to 300R is when I get the maximum voltage, 1.75v, and maximum...
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    Cobra 29 High Power mod with 2sc1969 transistor

    Okay, I think I have some 5.1V zener, bigger I don't think. Could it be worth two zener in series of 3.3V? like 3.3v + 3.3v. Yesterday I tried to vary the value of R2 both higher and lower and it only managed to decrease the value of the voltage, but I don't remember what value of R1 I left at...
  11. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Hello. Swapping 1n4148 with 390R voltage up to 1.4v but power output the same, 3.8w. If i use 3.9k and 470R the voltage down to 1.25v qnd power down to 3w. :cry:
  12. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Thanks. I have swap diode with 390R resistor, and the gate voltage up to 1.4v, but the output power is the same, 3.8w.
  13. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Yes, I am using what you recommended: 3.3KΩ - Orange - Orange - Red 390Ω (ohm) Orange - WHITE - BROWN - and the Diode a typical 1N4148 With this I get the 1.2V you asked me. This value can guide me in something? I saw those posts, but since the text is embedded in the photo, I don't understand...
  14. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Hello! The Gate voltage is 1.2V, both in AM and FM, I don't know if it is low or normal. I am very lost, and I know that you are busy. I'll wait until you have time so you can guide me, I don't know what else to try. My barrier is 3.8W. I have a pair of 2SC2314s on the way (I hope they are...
  15. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Test 2: With L13 4.5 turns, with core adjust, max 3.8w. After i have removed EKL and the power down to 2.5w. Curious, the max power that i have obtain with the irf520 is the same original power with 2sc2078. Maybe some component is damaged??
  16. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Hello, test1: C72 back to 220pF C74 out C75 original 47pf value C77 back to 150pF C73 220pF With EKL L13 3.5 turns without core Power: 1.1w L13 3.5 turns with core max inside, 3.8w. AM power when i talk down from 3.8 to 3w. I go to put L13 4.5 turns.
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    Cobra 29 High Power mod with 2sc1969 transistor

    These are the photos, one is out of focus, now I have the phone without battery and the flash does not fire. They serve?
  18. T

    Cobra 29 High Power mod with 2sc1969 transistor

    Do not worry, I give you time, it is already dark here, until tomorrow afternoon I will not be able to try more, also, I want to do it with some time, I do not like to make changes in 5 minutes, today I have been 2 hours. I have seen that the schematic of the 5001z, the part of the power stage...
  19. T

    Cobra 29 High Power mod with 2sc1969 transistor

    I have install a core into L13 and with some adjust i read around 3w in FM and 3.8w in AM. Maybe i need one turn more into L13, this coil is 3.5 complete turns. If i speak in the micro, the power in AM down to 2w.