After getting the vertical up, I set to putting the SB-200 back on the air as well. Last time I shared SB-200 stuff with you guys was when I just about killed myself by sticking my hand in the chassis with the HV power applied. I definitely learned my lesson and took many extra precautions this time around. Getting the SB-200 out of storage and converted back to 120v (no 240v in the new shack) I noticed the softkey circuit I had was not working, there was no keying action. The circuit was powered by a 3v lithium coin cell so its no surprise. I thought while I was in there, I'd rework the 12VDC power rectifier I built for the PC fans I put in there in our last blog post.
Since I was running the amp on 120v I wondered if I could improve the performance with the lower source voltage. With the exception of the soft key and the fans, I'd made zero modifications or updates to the amp. Surprisingly the amp was totally untouched and working great all things considered. And yet, I had picked up replacement capacitors for the power supply when I bought the amp at Hamvention so I figured it was time to just replace the aged ones in the amp. You've probably seen pictures like the one below on the internet and I always thought, "oh that's a blown up cap," but it turns out that's just the glue that goes in the paper covers! All 6 of the caps in my amp, did end up being absolutely fine, but I did find a bad diode which I also replaced.
Yeah now I'm running 1 KW......
more to come!