2950 low RF output

31 · Post by 31 » Saturday 16th Aug 2008, 16:22

I bought the radio with no audio out just a 1/2 watt dk in AM , SSB has audio but with low swing of 1 watt to 3 watt swing. After adjusting VR14 I was able to get back some swing on the AM, 1/2 watt swing to 1 1/2 watts. I have no RX . I have a Fluke 77 but no RF probes so vlotages cannot be read for an alignment. Any help would be greatly appreciated.

Rick · Post by **Rick** » Sunday 17th Aug 2008, 10:58

You do not give the model and PCB number, see www.radiomods.co.nz/forum/viewtopic.php?t=312

The low TX power is most likely a bad driver.
No RX audio is most likely the audio IC.

31 · Post by 31 » Sunday 17th Aug 2008, 20:49

Sorry Rick, EPT295011Z , If the Audio IC is bad wouldn't I lose the audio through the PA

Rick · Post by **Rick** » Sunday 17th Aug 2008, 21:45

31 wrote:I bought the radio with no audio Which audio RX or TX? out just a 1/2 watt dk in AM , SSB has audio but with low swing of 1 watt to 3 watt swing. After adjusting VR14 I was able to get back some swing on the AM, 1/2 watt swing to 1 1/2 watts. I have no RX . I have a Fluke 77 but no RF probes so vlotages cannot be read for an alignment. Any help would be greatly appreciated.

There is on reference as to what test you have performed.
Therefore, we have to guess what the most likely fault is. That why we ask for all the information you can provide.

What is the voltages around the mic amp (IC16) in RX and TX?
What is the voltage at the base of Q51 in AM mode TX?
What is the voltage at the collector of Q51 in AM mode TX?
What is the voltage at the emitter of Q51 in AM mode TX?
What is the voltage at the collector of the driver and final in AM mode TX?

31 · Post by 31 » Wednesday 3rd Sep 2008, 6:19

Rick,
Got it working, PLL was way out. I need to align the TX section again. Thanks

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2950 low RF output

2950 low RF output

Re: RCI2950 low RF output

Re: 2950 low RF output