Gene Heskett wrote: > On Friday 28 June 2019 02:14:42 deloptes wrote: > >> Gene Heskett wrote: >> > There was a period a decade back where the capacitors >> > were legendarily bad. Your unit may have some of them in it. >> >> It was around 2004. From a trustful source I understood that the >> Chinese manage to steal the formula from Japan, but translated few >> things wrongly and the world was flooded with bad caps. In the company >> I was in back then, PC caught often even fire. We had to mitigate the >> risk or just replace the PC with more reliable once. This was a good >> story. > > I think your beginning date is likely right, but it took a looong time > for those to get flushed out of the supply pipelines. They typically > went for 10% of what the good stuff was worth and a lot of buyers with a > BOM in hand thought they were getting a good deal. > > Electrolytic capacitors are a very old tech. I even caused a shortage of > American made caps in the middle of the OPEC battle in the '70's. I was > at the time a tx supervisor for Nebraska ETV, in charge of a channel 19 > site NE of Norfolk NE, getting pretty close to colder weather and > needing a barrel of Technical Grade Ethylene Glycol for making a 30% mix > for transmitter coolant. As that was a klystron using transmitter, you > had to have extremely pure, as in distilled or better coolants else the > voltages involved would corrode the plumbing very quickly from galvanic > effects. Anyway I ran up quite a phone bill locating a barrel, finally > finding it sitting on a shipping dock in Omaha, and bought it on the > spot, paying about $14/gallon. I had antifreeze for the winter, but that > barrel was the last in the country, and was scheduled to be shipped to > Sprague in Lincoln about 3 weeks after I bought it off the dock. Put > Sprague out of the cap business for several months and created a > nationwide shortage of replacement capacitors for the tv's etc of the > day. It was well into the next summer before caps started showing up in > the wholesalers shelves again. > > That rise in energy costs broke a few broadcasters and sounded the death > knell of klystron amplifiers. It did take something over a decade to > flush them, the last time I was one was in 87 or 88, when I was coerced > into going up the WNPB, near Morgantown, one of the State of WV's > educational tv stations, to see if I could get them back on the air. > > Poor operator education caused them to wreck one, and they had no real > money to buy a new one at $130,000 or so from Varian. But this was late > April or early May, and the legislature had included money for a new > transmitter, available after 1 July. So they bought a used one that was > full of air, then another used one that might have been usable had the > half moons in the shipping crate been reinstalled. But they weren't, so > I unpacked it, checked for gas, found very little so it seemed worth > dressing it up with its cavities, setting it in the magnet dolly and > trying. It wasn't until I was trying to seat it in the dolly that I > found it was bent. At that point all the state engineers declared it > would not work. But I thought we had one chance, and by then I was > convinced I was the only one in the building who actually knew how the > darned things worked. So I scouted around and found some masonite and > cut a couple pads out that could be wedged between the magnet coils and > the corners of the top cavity, and placed them such that the tube was > centered in the coils again. > > Measureing for center, I placed the iron places called wobble plates > back on top of the dolly and wheeled it into the cubicle & hooked up the > plumbing. Then I set the supply feed to Y which cut the beam voltage to > about 10K volts, and raised the accel voltage as high negative as it > would go, said a small prayer and brought up beam power. Body current > was high so I had a limited time to see if moving the wobble plate would > reduce it to a tolerable level, and it did. Then I lowered the accel > toward ground, wash, rinse, repeat. Put the beam supply back in delta > mode, wash rinse and repeat. About that time I became aware that the > beam was catching the gas ions and was carrying them to the collector > bucket and probably burying them in the copper. Any way, a few minor > tweaks and a tube they only paid 10g's for used was on the air at 85% > power and a safe and slowly falling body current. And the other state > engineers finally understood they had been watching someone who knew > what he was doing. And while I was by then tired, it was about a day > before the grin let my ears come back to their normal position. I spent > far more time teaching the young operators as they came on duty how to > keep it adjusted than I did trying to teach the engineers observing me > being a nerd. After all, they'd been to school, had sheepskins on the > wall. I've an 8th grade education, but have never stopped learning. > They had. > > Cheers, Gene Heskett
If I had the time I would extract all of your good stories from the debian users list and put them together regards
