discharging caps

Any date on that image file?

Just for interest's sake.

Looked up the junk image here - mine have brazed radial stranded (steel) leads ending in male fastons.

Putting terminals on a glazed structure must drive somebody nuts.

Not sure heatsinking helps for pulse ruggedness below a few seconds but minutes - yes.

For running hot, consult the literature.

RL

So did I:

Phooey to you too.

hmmm. The one in the posted zip file says 'last modified' in March, 2009. Sure you're reading the right info? 'date created' in windows is just the date of last file transfer or 'saving'.

RL

Wanna start a flame war over the photo date?

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

You did get it wrong.

Is it important to you?

Sad.

Getting stuff right is important for most people. Psychopaths prefer impressing people to informing them. They don't feel bad or sad when they get stuff wrong. It is a pathological condition.

When the file is open, it may show 'properties' that are more literally informative.

I'm just trying to jog my memory, which is no longer what it used to be . . . . not joking.

RL

The date fields of a 20-year-plus old photo of a resistor, copied many times between various PCs, posted to Dropbox, all this done by various versions of Windows and Linux, gives you fodder to debate wrongness.

That's really sad.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

I had some relevant experience yesterday:

I was working on a radio transmitter with a 750 H.T. rail and had switched it off to make some changes to the circuit. As I leaned forward with my hand on the chassis, the palm of that hand touched the H.T. tag on a tagstrip and I received a painful elecric shock and some superficial burns.

It appears the discharge resistors in the power supply had gone high resistance and were taking a couple of minutes to pull the 750v rail down to 100v. Given the time interval between switching off and getting the shock, I estimate it must still have been around 700v from a couple of 100uf capacitors in series.

I don't have any suitable discharge resistors in stock and I and have no intention of doing their job for them a second time, so I have glued a strip of plastic along the top of the tagstrip as a temporary measure. I will order some replacement resistors ASAP and am happy to report that the burn marks have almost disappeared

Afterwards, did you decide you were an inductor or more of a capacitor?

I like to have at least two red LEDs visible when nasty voltages may be around. Current limit with depletion fets to get linear discharge and full brightness almost all the way to zero.

Fingers have impressive ability to supress oscillations. I want a surface-mount part that behaves like a finger.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

What's sad is that you couldn't work out what the right data-field would have been (the date when the photo was taken) and post that.

Given the vintage nature of this equipment, a neon indicator would be more appropriate. It also extinguishes itself at around 85V, which is regarded as 'safe enough' to work on.

Normally I would expect the H.T. to drop almost immediately if the power was cut because the two output valves (6146) draw over 100 mA but I had unplugged them because there was a chance that they might be damaged by

I developed a definite resistance to doing it a second time.

You sure it wasn't reluctance?