How long does a CRT keep its' CHARGE?

[SnotRockit]

I'm going to attempt to change the chassis (E07) on my CRT and so I need to remove the old one. I was just wondering how long does a CRT hold its' charge? I have looked at the steps required to discharge the CRT and it's got me a little scared...all this talk about 30,000volts, etc.

The last time this CRT got any power was about 1 week ago...(to test it). It has been unplugged since then. Is there still a charge in the CRT and if so, could it still be as high as they say (ie. 30,000v)? I'm just nervous about even discharging it.

Any help is greatly appreciated. Thanks.

SnotRockit

[ChadTower]

Can be quite a while.... and it can rebuild the charge, although at a much lesser current rate, after it has been discharged once or twice.  If you're ever in doubt do the discharge.  If you're too nervous to do the discharge don't try the swap.

[Kevin Mullins]

Rule of thumb is "FOREVER" and "ALWAYS".
(gotta play it safe)

[northerngames]

I would not put my faith in that method your best bet is to do it the right/safe way instead of getting jolted and a doctor bill that cost more then the cab your toying with.

on top of that you may cause even more unwanted damage to other components and make it even worse

[Kevin Mullins]

I would not put my faith in that method

Which method would you be referring to ?

[Rickn]

A few things regarding the "discharge"
- first off the charge on the tube is " static" this means one shot .. it will not kill you unless you have a severe heart problem. Biggest danger is dropping the tube because of the shocking surprise.
- next the charge is due to the internal capacitance of the tube, this means that depending on the tube it may last longer or be stronger. It may actualy recharge after being discharged.

Yes Discharge every time you handle the tube... I don't but after years of getting hit I am used to it.

Rick

[Kevin Mullins]

Yes Discharge every time you handle the tube...

My point exactly.

And yes.... I have been put flat on my duff by a crt before.

[Cameronj]

Yeah my buddy unloaded a monitor on himself a couple months ago. Not knowing anything, he wanted to see what was under the suction cup thingy.

Didn't hurt him, but scared the crap out of him.

[Kevin Mullins]

Well, I know a recently charged older 25'er will make you do something to the effect of  "unnnghghgh" and will sit you down for a bit to regain some form of mental state that is measurable.
 

So yes, please take proper precautions and properly discharge any crt monitor prior to removing the chassis and or anode lead from the tube regardless of how long it's been unplugged or turned off etc.
And then do so again prior to re-installing any said chassis or anode lead or prior to handling the tube as long as the anode is detached. (that little hole in the tube could bite)

[northerngames]

I would not put my faith in that method

Which method would you be referring to ?

by the initial post I was assuming he was asking if it was safe to just pull it without discharging it and therefore putting his faith in it in hopes it died out by letting it sit for x amount of days to lose the power.

therefore I would not suggest using that method understood now?

[ChadTower]

The rhythm method is not reliable - make sure to dump your discharge properly.

[Kevin Mullins]

by the initial post I was assuming he was asking if it was safe to just pull it without discharging it and therefore putting his faith in it in hopes it died out by letting it sit for x amount of days to lose the power.

therefore I would not suggest using that method understood now?

Ah ... understood now ... and I absolutely agree.
Do not trust ANY crt tube regardless of how long it's been sitting around.

[shardian]

I prefer the CN method:

You invite Chuck Norris over, then he will give the monitor a stare icy enough to make the tube crap out all its charge.

For an extra payment, he will instead roundhouse kick the charge out of the monitor.

[ahofle]

The rhythm method is not reliable - make sure to dump your discharge properly.

Yeah I've had good results with the 'pearl neckboard' discharge method.

[leapinlew]

The charge lasts exactly 27 hours and 13 minutes. After that, it's safe to lick all the components in/around/on the monitor.

Nice knowing ya.

[ChadTower]

The rhythm method is not reliable - make sure to dump your discharge properly.

Yeah I've had good results with the 'pearl neckboard' discharge method.

Or you could just stick it in the anode to begin with.

[Thenasty]

Rule of Thumb.

Always Discharge no matter how many years its been sitting, never assume its discharge, don't ever stick your finger in the hole men always seem to stick something in a hole (it's not a rule, but it's a habit). 

[ahofle]

The rhythm method is not reliable - make sure to dump your discharge properly.

Yeah I've had good results with the 'pearl neckboard' discharge method.

Or you could just stick it in the anode to begin with.

That would be ideal, but unfortunately for me my monitor's purity rings won't allow that method of discharge. 

[ChadTower]

That would be ideal, but unfortunately for me my monitor's purity rings won't allow that method of discharge. 

Try swapping the chassis.  Maybe the next one won't have that problem.

[ahofle]

I think you're right.  Even a brand new set of shiny caps sure as hell didn't get me anywhere with this one. 

[ChadTower]

I think you're right.  Even a brand new set of shiny caps sure as hell didn't get me anywhere with this one. 

It's not much use sticking with a monitor that won't give you good B+.

[ahofle]

 
you win

[ChadTower]

Damn.  I had a great black level joke lined up.