[Boatanchors] SR-160 Problems
bob145 at suddenlink.net
Fri May 9 07:17:43 EDT 2014
I have a good friend who has one of these little beauties that he bought at a local hamfest. Below is his account of his first attempts to get it on the air which were somewhat less than completely successful. He's not a subscriber to any of the BA lists so I'm making this post for him. I'll pass along any suggestions you may have to get things resolved. His name is George.
Thanks and 73 to all.
Receiver worked well, and then I got a key and adjusted the bias current for the xmitter. Couldn't get it down to the recommended 60 mA; lowest it would go was about 70 mA.
No biggie, I thought. The output tubes looked happy, no bright red plates. I keyed up the xmitter on a real antenna, and it tuned up nicely. Was able to peak the Final Tune with the carrier, although the carrier pot didn't seem to do anything. Then I saw a little smoke, and a couple of resistors fried, one open circuit, the other closed. One was a 10 K, another near fry 10 K and the third a 22 K. I suspected the last person to replace caps may have had some leads touching, and I opened up the space and replaced the burnt resistors. The diodes seemed ok, as did the caps. The unit fired up and received like a champ. It tuned up as well.
But the 10 K that shorted before and was replaced was getting cooked. I have an astatic microphone, with the small amp underneath, which was properly wired to kick the unit into xmit, and it did so, but with very poor modulation. The tubes check out, and I replaced the sick one (a 12AX7 missing one triode) and some weak ones. I think the unit had more wrong with it than originally advertised. Know anyone who repairs these properly? I kinda like it.
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