I've been in Amateur Radio since 1974, and still find new and interesting things to do. I like to build, restore, and operate on the air. This blog has been running for many years, so be sure to check out "Jump to Posts on Specific Topics" in the RH column to drill down and find lots of stuff. Visit www.WB4IUY.net for the lowdown at WB4IUY. Email me at email@example.com if you have any questions.
This isn't my first rodeo with this 40+ year old rig from the mid-70's. It uses a dual gate N-Channel FET for the 1st RF amp... It's very sensitive (single tone detectable down below .01uV!), but it is also easily blown. I think this was knocked out when lightning struck a tree about 100' away. I repaired it last back in 2015, when I fried it while operating full tap on the 160 m band, when the 160m antenna was only about 10' away from the 2m SSB yagi :-)
I snatched the case off of it to have a look...it was only hearing about 3uV minimum, but when I injected a signal on the output of Q47, it came alive. Yep, bad FET.
This is Q47 after I removed it. I dug around in the junk box a bit, but didn't have any more of those. This was a ELM222, but the original was a 3SK40.
Well, I scratched around in my spare parts and found a RCA 148085, similar to a NTE222, and decided to give it a try. Sure enough, the receiver sprang to life and has a really sensitive front end, now.
Q47 as seen on the schematic...
This is the bag of the one FET I found in the workshop with a suitable operating frequency range.
Here's the IC-211, back in it's operating position and ready to go. I was able to work Alex KC4PHJ over in Apex and was hearing him fine, so combined with the rebuilt 2M SSB antenna I put up last weekend, my 2M SSB station is back on the air!