Spark while discharging 128K flyback

[falen5]

Camera rolling while working on the 128k caught this lovely sight

This is the flyback of a Plus analog board that I just transplanted onto this 128K analog board.

There were actually 3 sparks but what ever way youboob compresses video I only see the first

So this 'tiny' , 'harmless' looking spark is the one that can kill you ?

 

[falen5]

Meant to say "This is the flyback FROM a Plus analog board that I just transplanted onto this 128K analog board

 

[LaPorta]

Looks like it shorting to the tube itself...is the dielectric grease no longer present under that suction cup?

 

[dv-]

Neat.

 

[3lectr1cPPC]

I finally got a spark discharging a laptop power supply I was recapping - but on the two smaller output caps, not the large one on the HV side, which surprised me.

 

[cheesestraws]

bzzt.

 

[LaPorta]

I've never gotten a spark...but at leas two times I had tetany of my fingers by putting my thumb on one side of the mains on a Plus AB, and my index finger on the other, creating a nice U-shaped path for the electricity. I had to physically pull my arm away because the finger muscles were in tetany from the electric current, so I couldn't release them.

 

[joshc]

You only tend to get a spark on the pre-SE compacts because there's no bleed resistor. It's sort of nice because at least you know it's definitely discharged when you've seen/heard that spark.

 

[falen5]

All the machines from the SE onwards have a bleed resistor but I ALWAYS discharge them - dont know if the bleed resistor is working on them - but as for the original question, that spark is the high voltage right ? and could be enough to throw you across a room , blow a finger off or even kill you - they are some of the stories ive heard over the years - Heard of a tv repair man ( bout 30 years ago ) that apparently has his thumb blown off from a flyback .......... can any of these things be possible from that 'little' spark ?

 

[cheesestraws]

the physical size of the spark you can see isn't a particularly good guide to the amount of energy being transferred in it

 

[falen5]

hi cheese - I know it has thousands of volts , it just 'sounds' small - I once sheered a 3 phase cable in a factory with fork lift - blew me and the 5 ton lift into the air and the noise of it was terrifying - accidently shorted an electric forklift battery once while refitting straps , again the sound was terrifying - worked in place once with an electric arc furnace ....... OMG the noise of that thing was horrific , end of world kinda sound !!! but this little spark 'sounds' so small ....... again you wont see me taking any chances with it , i dont even jab the wire in with my hand , i use a pliars to shuv the wire into the anode ......... how many volts are coming from that flyback anyway , 10,000 volts ?

I fixed the 128K on the other post below - i swapped out the 128K flyback with one from a Plus - put a load of pictures of the blown flyback - scary stuff

 

[AndyMc1280]

hi cheese - I know it has thousands of volts , it just 'sounds' small - I once sheered a 3 phase cable in a factory with fork lift - blew me and the 5 ton lift into the air and the noise of it was terrifying - accidently shorted an electric forklift battery once while refitting straps , again the sound was terrifying - worked in place once with an electric arc furnace ....... OMG the noise of that thing was horrific , end of world kinda sound !!! but this little spark 'sounds' so small ....... again you wont see me taking any chances with it , i dont even jab the wire in with my hand , i use a pliars to shuv the wire into the anode ......... how many volts are coming from that flyback anyway , 10,000 volts ?

I fixed the 128K on the other post below - i swapped out the 128K flyback with one from a Plus - put a load of pictures of the blown flyback - scary stuff

This is why I got you to do the SE/30. Not yer forklift levels of shorting but even this going bzzt I'd crap myself !!

 

[dv-]

the physical size of the spark you can see isn't a particularly good guide to the amount of energy being transferred in it

I heard somewhere (maybe a YouTube video about residential electrical work? I deep dived a bunch of those after I got my house) that the voltage/amperage required to screw with your heart is too low to show a visible spark/arc in most situations. So I tend to figure if you can see it you should avoid it.

I know there are exceptions and it’s more complicated than that but it still seems like a good rule of thumb.

 

[68kPlus]

Dang. I've never had a flyback spark on me before, I always wait too long or it has a bleeder installed.

 

[LaPorta]

I always do the screwdriver-under-the-cup thing no matter what.