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Posted by: neil wa4chq Posted On: 03/23/01 Subject: sst problem Message Posted: Greetings all.... I am building the SST-40 from scratch and had completed the receiver a few days ago. It worked the first time. Started putting the xmitter section together and finished this afternoon. Keyed the xmitter and had no output to the final and in the process of making some tests shorted something in the receiver circuit. I can hear hiss in the headphones. One thing I first noticed was the LED in the AGC ciruit did not blink like it did before when I removed the power. So I started bridging components to see if I could fix it. I thought that C39 was bad because I found that by taking a new 470 uF elec cap and bridging C17 100uf then putting it back across C39-470uF, I would started receiving signals, but it slowly faded until the cap discharged. I wouldn't think the U3-lm386 was damaged if I am hearing a hiss and then getting a signal for a brief period. Or maybe it is shot. I am not sure where or how to trouble shoot this. The schematic from the QRPp Spring '97 issue didn't have the voltages. Anyone familiar with the SST have any suggestions? Thanks Neil wa4chq |
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