expansion bottle

[KOY 23]

Philip.
Maybe should be on the AGM agenda?

[Philip Wardle]

For added entertainment at the AGM we could follow Richard's lead. I have already rehearsed this, when I was a teenager 50 years ago I used to build electronic equipment using valves. Electrolytic HT smoothing capacitors in aluminium cans explode spectacularly if you apply 400 volts DC the wrong way round.They generate loads of metal shrapnel and large quantities of smoke and soot.

It wouldn't have been so bad if it was in the shed, but it was in my bedroom where there was a small workbench in a corner. It was a bit difficult to explain events to mum, luckily she didn't let on when dad got home from work. He was busy designing the thyristor drivers for exciters on the 660 MW turbo alternators at Drax power station. I remember speculating as to what 660 MW would do to my electrolytic capacitor.

[trunt]

For added entertainment at the AGM we could follow Richard's lead. I have already rehearsed this, when I was a teenager 50 years ago I used to build electronic equipment using valves. Electrolytic HT smoothing capacitors in aluminium cans explode spectacularly if you apply 400 volts DC the wrong way round.They generate loads of metal shrapnel and large quantities of smoke and soot.

It wouldn't have been so bad if it was in the shed, but it was in my bedroom where there was a small workbench in a corner. It was a bit difficult to explain events to mum, luckily she didn't let on when dad got home from work. He was busy designing the thyristor drivers for exciters on the 660 MW turbo alternators at Drax power station. I remember speculating as to what 660 MW would do to my electrolytic capacitor.

Haha!
Been there done that! But it was in the attic. I learned that the 500v supply for the oscilloscope display tube was a negative voltage and previously I had always wired capacitors with negative to chassis.. somehow I was not blinded. Dad didn’t seem overly concerned.. well it was the early 70’s

Did you ever blow a selenium rectifier? What a stink!!

[Lingen]

I would never have guessed that my remark on the 11th would lead us on to exploding selenium rectifiers.
What a mine of information the Forum is if you dig in the right place.
Mike..

[Philip Wardle]

Yes indeed Terry, in common with myself selenium rectifiers develop problems as they age http://www.youtube.com/watch?v=zU8C5p7CQ_c although I have yet to catch fire. If anyone is still using a battery charger from the 1950's it may well have one. If you prefer old school tech its easy to replace the original rectifier with a modern diode. The charger may well have a decent transformer which will outlast the rest of us.

[richardthestag]

Now I remember them, another wasted* afternoon on yootoob watching silly things. And it all started with that video Philip Wardle

This gent is on my watch list, breaks stuff down and makes it make sense to electric imbeciles like me https://youtu.be/OOA1NaoKV6I

[Philip Wardle]

+1 Richard

Big Clive is always worth a look - other people seems to agree, he has 944K subscribers. If anyone is seriously into vintage electronics I can also recommend Paul of "Mr Carlsons Lab" fame on YouTube - one of the most professional and interesting channels out there.

[Wheelz]

^^^ +1 for Big Clive His ability to reverse engineer a circuit is admirable.