| Electronic M |
11-18-2013 01:11 AM |
This just goes to show some of the worst post power up set failures are caused by the technician. :p :D
Seriously though most major smoke outs I've experienced were my own doing... I made the mistake of wiring the replacement doubler diodes backwards in my old Split chassis Philco which caused the good original caps to overheat, and then I replaced the 100 something uF doubler caps with a bunch of 22uF caps in parallel. I had it on a variac and had it almost up to voltage when I went to the dining room for diner...Some time later I started hearing regularish faint popping sounds from my room I ran back from the diner table and discovered that those 22uF caps were exploding one by one. :yikes: About halfway between then and now I smoked B+ power resistors in two different rectangular Color sets from shorts. The first was my Zenith Chromacolor which during a focus repair (during reassembly after doing a cateract removal) I dripped solder on one of the above chassis terminals. I found that the original resistor smoked out so I just replaced it rather than trying to determine the cause...The replacement was an aluminum heat-sink cased dale power resistor. That thing went with a BANG! the moment I powered the set on. The other set was a single section of restuffed lytic that I wired backwards amazingly I was able to replace the resistor and reform the cap on my heathkit C-3 so one new resistor and cap wiring re-reversal later all was well.
The only hardcore old age cap failures I can recall were in my 9-T-246 I gave it a test power up and since there was no raster I feed a signal into the phono input and listened for a few minutes until smoke started creeping out and wax started dripping from a horizontal stage cap that let go. Later in that set's restoration I had replaced most of the caps except for two of the lytic cans....Then shortly after power up one of the cans started to hiss or whistle as the electrolyte boiled out the bottom.
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