On Sat, Jun 29, 2019 at 8:04 PM Gene Heskett <ghesk...@shentel.net> wrote:
> On Saturday 29 June 2019 19:05:23 deloptes wrote: > > > 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 > Be my guest, but give me attribution. I've even been tempted to write it > myself. Its pure serendipity that seems to have put me in the right > place at the right time. I am on this list just for Gene’s stories. > > >
