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I have an old 2K2 that I picked up a couple years ago. I've fixed a
few problems, with some help off the news groups. I used to work on this kind of thing on a daily basis, but that was 40 years ago ... sigh At any rate my trouble shooting skills are getting a bit of practice. One annoyance, not really a problem is a hum or buzz that gets louder with increasing plate current. I think it's the plate current overload relay. What is a good way to quiet this thing down mechanically? I guess I could build a solid state trip circuit which would be silent and they aren't very complex, but I would like to keep the thing more or less stock. The only real things I've found wrong were the meter switch was misindexed. I still haven't figured out how that can happen when the indexing is internal. There were no signs the switch had ever been taken apart either. I did take it apart and put it back together so the indexing was correct. (I used to do instrument repair and calibration in another life oh so many years ago.) Another problem was the bias module (diode with resistor and capacitor network) was shot causing high idle current and the forward power indication doesn't work. As the reflected does, I'm guessing the diode in the sample line is bad. The previous owner had replaced the power transformer with a "Huge" Peter Dahl unit that is considerably larger than the original. The filter choke is as big as the plate transformer in my HT-33B. Some where along the line, someone modified the bias and the SWR circuits, but nothing that can't be deciphered. At any rate, it's getting closer to being back on the air. Actually I can use it now, by inserting a diode, resistor, and capacitor in place of the failed diode network...I've tried it, but I'm waiting for the correct unit from the factory. OTOH, I'm tempted to just replace the whole thing with a 10V 25 or 50 watt Zener and bypass cap. I work a bit on the equipment, a bit on the shop and a bit on the airplane project...which means I don't move very fast on any of them, but I am making progress. Today was run conduit day. I installed two junction boxes. One outside and one inside the wall with a 2" pipe connecting them. A one foot stub of 1 1/4 emt comes out the bottom of the one on the outside and the inside one feeds a run of 1 1/4 inch emt conduit. That runs across the south half of the west end of the shop, up the corner and then over the garage door on the south wall with a drop down to the work bench. That outside box is going to get filled with foam (to keep the Yellow jackets out of the shop. Now that I've discovered the shop still has a floor, I guess it's time to do some cleaning too. Any one else notice how much extra time these "little jobs" seem to take? Roger Halstead (K8RI EN73 & ARRL Life Member) www.rogerhalstead.com N833R World's oldest Debonair? (S# CD-2) |
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