[BC] PCB and other hazards

[Milton Holladay]

I found a leaky non-PCB capacitor just a few days ago; it has a smell more 
like lighter or dry cleaning fluid--not very strong, though.
As to the Bird load, I had a 2500 watt unit that went way low in resistance. 
Opening it up revealed that the green fluid had somehow gone bad and had 
transferred some of the silver plating from the cone to the resistor. Bird 
said that they no longer used that type fluid and that the properties of the 
new type required a different design of cone and resistor to meets specs at 
very high frequencies......
M
----- Original Message ----- 
From: "Mark Humphrey" <mark3xy at gmail.com>
To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
Sent: Tuesday, January 15, 2008 1:03 PM
Subject: Re: [BC] PCB and other hazards


> On Jan 15, 2008 2:45 AM, Milton Holladay <miltron at mindspring.com> wrote:
>> Once you have smelled PCBs, you probably won't ever forget the 
>> distinctive
>> odor.
>
> I've probably smelled PCBs without realizing they were the source of
> the odor.  Richard said, "basically, if it smells, it may contain
> PCBs" but I would like to know how many of the substitutes are also as
> smelly.
>
> The reason I ask (some of you may have encountered the same
> situation):  A couple of years ago, I acquired a Bird 1 kW air-cooled
> dummy load, maybe 35 years old, which had been damaged by overheating.
> It had been exposed to 1.5 kw for an extended period and the
> resistance had gone over 10% high, so the station just decided to buy
> a new one.
>
> In the course of rebuilding it, I drained the oil, which was dark
> green, rather thick, and very smelly.  Orange sludge had been
> deposited in the bottom, around the resistor and the conical shield
> surrounding it, perhaps some kind of copper compound.  According to
> Bird's website, they have never used PCBs in any of their products, so
> I'm just curious to know what this stuff was.  I did carefully drain
> it into a bottle and took it to a hazardous waste disposal center.
>
> After doing some research, I determined that Bird currently uses a
> silicone-based oil.  There a distributor in Philadelphia that sells a
> similar product at a discount price, although the minimum order is 5
> gallons.  I only needed about half of that, so I split the order with
> a local ham who was also doing a dummy load rebuild.  Info:
>
> http://www.clearcoproducts.com/specialty_silicones.html#2
>
> The new oil doesn't have any appreciable odor.  With cleaning and some
> adjustment of the resistor termination, I got the resistance down to
> 52 ohms, so the load is now doing a adequate job again.
>
> Mark