开云体育

DOA - broken wire on T4, what else...?

Stephan Lauffer #26464 Hello! At the moment I am on searching for the next, for other problems to solve after I found a broken wire in the T4 (see ). With the broken wire the output for the speaker was very quiet. There was a birdie on TX (I thought about a mic problem with the baofeng hand mic...) and a very loud birdie at nearly lowest volume out of the speaker. Besides this broken T4 I found a broken R141. I don't know if this one was broken during assambling the board or if it blew up during my tests. RX looks good so far, but on TX there are only about 450mA power consumption (over all, not only the PA-PWR). There is only a very, very low increase of the power draw... I now would like to messure important points to check out what's wrong on TX. D20 looks good (imho, checked with my DMM, it is open at about 240mV and close in the other way). Should I check Q13, Q14, and Q15 now? How can I do this the best way? -- 73 Stephan DC8LZ
Daniel Isaza All Messages By This Member #26475 Hello Stephan, Sorry to hear about your problems building the BITX40, I just completed mine a few days ago. I also had the insanely-loud-birdie-at-minimum-volume problem but I was able to solve it quickly, I hope this helps: -Initially I connected the GROUND cable from the Raduino to the ground pin of the volume pot. --> LOUD BIRDIE! -Then I moved the Raduino ground cable to the back of the radio all the way to the ground of the power connector directly ---> PROBLEM SOLVED. I don't know about your other issues because eveything went pretty straightforward, just my two cents on the loud birdie volume issue. keep it up! 73, Dan HK4DEI toggle quoted message Show quoted text On Fri, May 12, 2017 at 9:30 AM, Stephan Lauffer <lauffer@...> wrote: Hello! At the moment I am on searching for the next, for other problems to solve after I found a broken wire in the T4 (see ). With the broken wire the output for the speaker was very quiet. There was a birdie on TX (I thought about a mic problem with the baofeng hand mic...) and a very loud birdie at nearly lowest volume out of the speaker. Besides this broken T4 I found a broken R141. I don't know if this one was broken during assambling the board or if it blew up during my tests. RX looks good so far, but on TX there are only about 450mA power consumption (over all, not only the PA-PWR). There is only a very, very low increase of the power draw... I now would like to messure important points to check out what's wrong on TX. D20 looks good (imho, checked with my DMM, it is open at about 240mV and close in the other way). Should I check Q13, Q14, and Q15 now? How can I do this the best way? -- 73 Stephan DC8LZ

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