Power boards on plasma tv s can shock you.

**BHNathan** · 02-12-2019, 11:21 PM

I was sorting all my electric board the other night and i put 2 power boards from the same plasma unit in the a box together. I believe the bottom of each boards were against each other. When i picked up the box there was a BRIGHT white flash and i yelled like a little girl and dropped it on my foot! For sure i thought the boards had been out of the TV for at least 2 weeks...maybe more. This was the first time i have ever had a LIVE electrical experience before since i am usually very cautious, until now apparently. I guess i should invest in some static proof bags!?!

**jimicrk** · 02-13-2019, 01:53 AM

I've been bitten by power boards a few times and I've seen the capacitors discharge as the boards were thrown into a box also. CRT's can get you also if you're not careful.

TheHoss can testify to that.

https://www.scrapmetalforum.com/scra...-possible.html

**auminer** · 02-13-2019, 06:56 AM

Closest I ever got was a server UPS board. It welded the screwdriver I was prying the heat sink with right to the board.

The rest got dunked in a grounded tub of water prior to disassembly!

**RLS0812** · 02-13-2019, 08:20 AM

Those darn capacitors can bit you many weeks after their last use.

The most dangerous are the high voltage caps .

**406Refining** · 02-13-2019, 08:52 AM

I have been bit enough times with those TV power board caps that I usually wear gloves when handling them and only hold the edges of the boards.

**greytruck** · 02-13-2019, 10:04 AM

I never had a problem with tv's, but I had a ceiling fan sitting in my driveway for over a week and it poped when i cut a wire coming out of the black box. SURPRISE! ! !

**hills** · 02-13-2019, 10:43 AM

I got zapped twice from a power board out of an LED tv the other day. It bit me so i ran a screwdriver over all of the capacitor leads to discharge the board. Lol ... thought it was okay to work on and got zapped again.

Humm ... ???

**JJinLV** · 02-14-2019, 04:24 AM

Shouldn't have read this thread. I deal with, at a minimum, hundreds of power boards each week all without incident and now I feel like I'm due lol

**DakotaRog** · 02-14-2019, 06:28 AM

[QUOTE]Shouldn't have read this thread. I deal with, at a minimum, hundreds of power boards each week all without incident and now I feel like I'm due lol [QUOTE]

Same here. Not that I handle hundreds of boards a week but that I've never gotten bit. I wonder how many e-waste boxes have started on fire en route to their receiving location because of this latent capacitor "activity"...?

**mikeinreco** · 02-14-2019, 08:02 AM

KNOCK ON WOOD but I have disasembled a few electronics and have never been shocked...........I have however seen a spark or two..........I wear gloves and use rubber handled tools so perhaps that could be the remedy

**Breakage** · 02-14-2019, 09:30 AM

Plasmas are probably the riskier board, owing to the higher voltages required for the setup. LED and LCD panels should be less problematic, unless the caps are for the starter (or whatever) on the actual lamp unit.

Shorting electronics is dicey business. One thing I have read that works for microwaves needing a quick d/c is to plug it in and drop it in a drum of water. I am certain I would be summarily removed from my job if I was found "dipping" larger appliances with a live charge so I have not tried it. That just feels like something not OSHA-approved. But for smaller boards, I suppose you could connect the power from the supply board to a power strip and just pour water over it. That sounds a little uncertain, though.

Also, as an aside, I had a spark on a defib unit but it was the lithium battery pack. I left it alone for a month to d/c the capacitor but those batteries were still packing heat. Are there permanently-mounted lithiums on TV boards? I don't see many of those so I am unfamiliar. They could be the culprit, too, though with all the cap problems flatscreen TV's have had in the last decade-and-a-half, I'd expect them to be the most likely spot for a spark.

**nutpie** · 02-15-2019, 09:33 AM

Not sure if this will help but I learned through refurbishing a laptop that if you unplug an electronic from it's power source and hold the power button it will drain the capacitors of electric current. I tried this and it worked on a laptop.

**eesakiwi** · 02-26-2019, 07:54 AM

I have been bitten by a stereo amp power capactor & a CRT when I cut thru the big red wire attached to the back of the screen.
Microwave capactors have a ' bleed resistor' across the terminals so in theory they should be discharged.
The exception probably is if you have plugged it in to test it, it's not worked so you scrap it right away.
That exception probably works on any electrical item too, if it's just been plugged in, even if it didn't do anything, the capacitors should be treated as if they are charged up.
Even microwave capactors.

A while ago I did test one, found it didn't work & started to scrap it down, I started on the platter drive motor underneath it & when I cut thru the 2 wires I got a shock.
Thats when I realised i'd been too hasty & hadn't unplugged it.....

Even if it's only a small shock, the danger can be elsewhere, like you get the shock & your arm jerks back & you slice yourself on something sharp close by.
Be aware of your surroundings.

**Stargate1** · 02-28-2019, 12:41 PM

I've only ever shocked myself twice. Both times were on CRTs I was scrapping after I had just plugged them in to test them. It was the lead-plated glass on the back of the tube that shocked me. Not a bad shock, but I found it was 24,500 volts of a shock when I read the sticker on the tube. That happened twice. I was in high school at the time, which brings me to this story: My physics teacher did a science lab where the kids bring electronic stuff in and take it apart (scrapping at school!). Of course, the teacher just gave me a free 100 since he already knew I did this every day outside of school. But, one of the girls (lol) brought in a larger CRT she found at a Goodwill for $5. They plugged it in to verify it was working. And then began taking it apart. They popped the back off, and was just standing there with the teacher as he was taking the back off. He was explaining something and pointing at the glass tube, the area which was plated in conductive material, and I kept saying "Don't do it, it'll shock you." He just said, "Oh, it won't be that bad." I just said ok. Not two seconds later, ZAP! I'll just say this- I'm glad the principal wasn't in the room because I'm sure my teacher would have gotten fired for what he said afterward. Plus, I think he learned his lesson. The sticker on this TV said 20kV. To this day, he makes the kids use a plastic rod to tap things a few times, and connect a grounded wire to the back of the glass to make sure there's no charge.
Sorry for the long story, but I thought it might be applicable here. Hope you enjoyed it, nonetheless.