Re: #ubitx-help #ubitx-help

Howard Fidel

OK. I will try to keep it simple. Lets take the example of Q10. It is not straight forward to calculate its operating point, because the bias voltage depends on the collector current, which is a function of the bias voltage. However, If you start R18, you should find about 12 volts on both sides of that resistor, since it is only 10 ohms. You should see a voltage drop of a few volts across R14, something between 4 and 10 volts would make sense. The two following transistors are emitter followers, so you should find 0.6 volts less on R15, and 1.2V less on R16 then you find at the collector of Q10.
Q30 is the same topology, so it should be similar. The other stages should be working since you have audio. You can also check with power off with your ohmmeter that you have continuity from the antenna input to the side of C204 that is not ground.  If you need more help. let me know.


On 6/3/2018 4:48 PM, hakan.sjostrom@... wrote:
Thanks Howard for all your help. By shifting the connectors my first thought was that the transistors should not be affected, but who knows.
Yes, I just have to go the hard way and measure as good as I can (don't have a scope). But if you can give some hints what the voltages for the transistors should be, it would be of much help. But you have been very helply so far, so I can't expect you to waste too much time on this.

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