CurtPalme.com Home Theater Forum

dobbar · Joined: 10 Feb 2008 Posts: 32

Although I've already done a glycol filter / change on an old sony 10xx without killing myself I've come over
all paranoid again about changing the HV leads on my barco data 500 (kindly supplied by Curt)

Should the process be :

Switch off - leave plugged in, discharge tube to earth, unplug. (makes sense to me)

OR

Something else entirely.

I have searched already and there are references to just unplugging and leaving the unit for a time, but I don't understand
how anything can discharge if there is no connection to earth. If any of the experienced crt tech's can tell me how
they do it i would be very grateful.

Thanks in advance.

perisoft · Joined: 29 Aug 2007 Posts: 2920 Location: Ithaca, NY

Personally, I'd just unplug and wait 24 hours. My dad's an EE and that was his recommendation. It's not like the stuff in there is a battery; it just CAN'T hold a charge indefinitely. With relatively small tubes as on CRT PJs you probably don't need to wait 24 hours, but I figure I might as well be on the safe side given the consequences...

Tom.W · Joined: 09 Mar 2006 Posts: 6635

http://www.youtube.com/watch?v=WX43sT0hMJk&feature=related

lostindiana · Joined: 15 Mar 2008 Posts: 21 Location: Federal Way, WA USA

From my experience with larger CRTs, they can hold a charge for quite some time, but I would say what you are thinking is pretty much right.

Here is an article on the process.

http://www.wikihow.com/Discharge-a-CRT-Monitor

I used to have a special tool for this and I remember the first time I discharged a CRT I was pretty nervous.
Sometimes you don't even get a pop sound and other times its pretty apparent.

What perisoft said is pretty much correct, they can't hold a charge forever, but I have gotten some pretty good pops with CRTs that have been unplugged for more than 24 hours.

-Michael

dobbar · Joined: 10 Feb 2008 Posts: 32

Cheers !

**AnalogRocks** · Posted: Mon Mar 23, 2009 4:30 pm Post subject:

You can also turn off and unplugg the projector from the mains for a while then if you want you can pull the HV lead from the splitter end and ground it to the chassis. I've pulled the HD leads many times on my Ampro and never got a shock. I always let it sit for at least 3 minutes.

And to the screwdriver under the anode cap trick, keep in mind the caps on our CRT tubes are siliconed on. If you do that trick you'll need to redo the silicone.

Mark_A_W · Posted: Tue Mar 24, 2009 5:40 am Post subject:

I measured the HV on an XG straight after turn off, using a HV probe and got zilch.

I think 15mins would be fine.