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William K.
User Rank
Platinum
Re: How much lead is there in a CRT?
William K.   1/6/2014 12:41:25 PM
NO RATINGS
Thanks for the information. I knew that leaded glass is stable, but I was not aware that the weight was that much. My guess is that is the total glass weight, rather than just the weight of the lead. And it would appear that the hysterical individuals who lobbied for the law never considered that it was not elemental lead in an active state.

But it seems that if lead could be recovered from leaded glass that there could be money made in recovering it because that might be cheaper than mining the lead ore and refining it. But possibly separating the lead from the lead oxide combined with the glass is not an economical process.

Mark Olson
User Rank
Iron
How much lead is there in a CRT?
Mark Olson   1/6/2014 8:12:39 AM
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Re: lead content of CRTs, the first hit when I googled for "lead content of crt" was www.premierinc.com/quality-safety/tools.../k_3_lead_in_crts.pdf‎.

According to that PDF:

Lead in Cathode Ray Tubes (CRTs) Information Sheet**

 

A CRT is used in most televisions and computer monitors (Liquid Crystal Displays (LCDs) and plasma displays do not use CRT technology). Lead is used in CRTs to protect users from potentially harmful exposure to x-rays. The lead in CRTs is bound in a glass matrix as lead oxide, and is stable and immobile. According to the data collected, the average CRT for the time period 1995 to 2000, including televisions and monitors, is an 18.63-inch CRT with a lead content that varies from 2.14 lbs to 2.63 lbs.

 

The table lists screen sizes from 8" (just over 1 lb of lead) to 35" (9 to 11 lb of lead). But, as you correctly point out, the lead is not strippable from the glass and it is chemically stable and not going to dissolve out when placed into a landfill.

 

William K.
User Rank
Platinum
Re: about that lead-free solder decision.
William K.   1/3/2014 3:56:47 PM
kenish, I rather doubt that any CRT of any size contains even a pound of lead, for shielding or for any other purpose. There is leaded glass, but there the lead is to make the glass more durable, I believe. Also, the lead in glass is rater tightly bound to the molecular structure, and not subject to leaching out in a landfill. So I would ask about where that assertion about lead shielding came from. With the scrp value of lead being quite high, the scrap collectors around here would be grabbing up every TV that is put out for the trash collection, and yet they are very seldom taken from the curb.

And if a $15 deposite does not bring about an adequate amount of rectcling, then perhaps a $100 deposit would. Also, it should be quite high for all electronics, not just large screen TVs. Cell phones and personal electronic devices should ALLL have the deposite.

kenish
User Rank
Platinum
Re: about that lead-free solder decision.
kenish   1/2/2014 7:28:55 PM
NO RATINGS
Here in CA an e-waste deposit is required.  I'm not sure of the exact amount but IIRC it's about $15 on a large flat screen TV.  Most consumers don't bother to recover the cost so there's community e-waste events where the proceeds go to local charities.  The parking lot at our local events looks like a loading dock for Best Buy or Staples with the piles of computers, printers, phones, and TV's.  That said, most e-waste is shipped to the 3rd world where materials are extracted under very unsafe and toxic conditions.

I agree that RoHS claims are very exaggerated, though a 27" CRT contains over 10 pounds of lead for X-ray shielding.  A friend in the space electronics biz was aghast when I brought up RoHS...they put as much lead as possible into their stuff!  I agree the cost and safety impacts of RoHS probably outweigh the trivial environmental benefit especially with e-waste recycling.  (Philips was very involved in RoHS and the exemption for trace amounts of Hg was ironic since Philips was bringing CFL's to market).

Back here in SoCal, I grew up remembering eye-smarting smog.  There would be 10-15 Stage 3 smog alerts every summer and we'd do PE indoors.  It's been 12 years since the last Stage 1 alert and much longer for a Stage 3...and there's a lot more cars if you've used the 405 Freeway lately!

 

 

William K.
User Rank
Platinum
about that lead-free solder decision.
William K.   1/2/2014 3:13:40 PM
NO RATINGS
I would agree that the original ROHS legislation and most of the expansions are based primarily on emotions by those unwilling or unable to consider facts and other inconvenient parts of reality. One of the very emotional articles recommending the removal of lead solder gave numbers that implied six pounds of lead were in each scrap0ped computer. A more realistic number would be closer to six grams.

The unfortunate unintended secondary consequences have been that a lot more electronic waste is produced, since the non-lead based solder connections are still not as good as the older solder connections were. So more equipment fails at an earlier age, and less of it is recycled, because there has not been any system for providing a real incentive to recycle.

As an example of what results can be expected, Michigan put a ten cent deposit on carbonated beverage cans and bottles, in order to reduce litter. It would have included all beverage containers except for the really strong lobby efforts from the industry. But the result is that one very seldom sees any of the deposite cans as litter any more. Now imagine what a $5 deposit on most electronics would do. Most of the items would be recycled, either by purchasers recovering their deposits or else by those same folks who glean all the cans from our landscape. So there would be a benefit in two different areas, and a large reduction in landfill-destrined electronic devices.

It is certainly an option worth considering.

tekochip
User Rank
Platinum
Re: Lead-free solder perhaps?
tekochip   1/2/2014 2:24:53 PM
NO RATINGS
I populated mine with LED lamps.  They're brighter, look better, run cooler and last forever.

While rohs has certainly been a technological millstone, many of the environmental laws have had quite sudden, and positive results.  As a kid growing up in the Sixties, there were few environmental restrictions.  It was normal to drive through Gary Indiana with your lights on because the visibility was so poor from smog.  DDT had decimated the top of the food chain so badly that I never once saw a heron, egret, hawk or an eagle.  By contrast, today alone I saw four bald eagles fishing on the Fox River, a river so polluted, as a boy that the fish retrieved while fishing were literally covered with tumors.
 
Yes, there is over-reach and some darn silly laws, like rohs, but without some oversight ever country can quickly become as polluted as China.


wbswenberg
User Rank
Gold
Re: Lead-free solder perhaps?
wbswenberg   1/2/2014 12:42:10 PM
NO RATINGS
Might have been the wrong orifices.  My brother-in-law had a problem with his Kenmore gas range.  No adjustment in the flame other than full on.  He was on propane and I guess they delivered a nat'l gas unit.  So we got on Sears Part found the model and ordered the orifices for propane.  I was not there but he installed and it fixed the problem.  I suspect you problem is the other way around.

Tom M.
User Rank
Silver
It's not just a solder problem
Tom M.   1/2/2014 11:17:00 AM
Was your PCB charred?  Mine was.  The problem is that the relay Bosch used to drive the heater element is very undersized for the application.  The maximum rating of the relay is 10 A at 120 VAC, and it drivers a 1 kW heater.  The relay runs very hot, so much so that it chars the board and even melts away the solder.  Resoldering helps for a while but unless you replace the relay it will burn the board away again.

Search youtube for "bosch dishwasher relay" you'll find explicite instructions on repairing the board.  I found this link particularly good http://www.youtube.com/watch?v=Jb8gAnMb2zQ and http://www.youtube.com/watch?v=3nLN3WO3RQY.  The only difference I found was that my board used a 12 V relay vs. the 6 V one the videos called out, I got it from MCM electronics part #R46-5D12-6 for $4.


Tom M.





Tool_maker
User Rank
Platinum
Re: Lead-free solder perhaps?
Tool_maker   1/2/2014 11:00:06 AM
NO RATINGS
  Is there a web site that lists the problems that have been caused by environmentalists over reach? I am currently mourning the soon-to-be disappearing Incandescent Lightbulb and wondering what I am going to do with all my ceilng fixtures once my stash of 60w bulbs is gone.

Tool_maker
User Rank
Platinum
Powers of Observation
Tool_maker   1/2/2014 10:54:13 AM
NO RATINGS
  I am not an EE nor do I have the equipment to test that I often see mentioned in these posts. However I have been able to do many household appliance repairs simply by looking for loose or dirty connections. Clean and/or solder and away it goes. Sometimes I do not even know what I did, but the problem is fixed so all is cool.

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