I just looked at the MRF-644 data sheet and it makes no mention of Beryllium Oxide with the usual health warnings.
At the moment I think the burning sensation in my chest is heart burn at from the onions on my Double Double I had for lunch. On 3/21/08, skipp025 <[EMAIL PROTECTED]> wrote: > > One of the main issues with Beryllium Oxide is to not breath > any of the dust when it breaks, is ground on or sanded. I work > with it every so often and actually can and do repair broken > Beryllium oxide parts for industry, which include some of the > blocks found in rf amplifiers. > > cheers, > skipp > skipp025 at yahoo.com > > > > "Stu Benner" <[EMAIL PROTECTED]> wrote: > > I am ignorant about the particular parts you are discussing. > > However, caution should be used when dealing with ceramics > > such as this. They may be Beryllium oxide which has excellent > > thermal conductivity and electrical insulation properties, > > however, it is a carcinogen. A web search will reveal lots of > > information on the material. > > > > Regards, > > Stu > > W3STU. > > > > -----Original Message----- > > From: [email protected] > > [mailto:[EMAIL PROTECTED] On Behalf Of DCFluX > > Sent: Friday, March 21, 2008 11:48 > > To: [email protected] > > Subject: Re: [Repeater-Builder] Anyone have a Motorola house part number > > secret decoder ring? > > > > > > > > I had to grind the flange and ceramic of the 4062 with my dremmel to > > make it fit the PCB in the FT-857D. Took me 3 PPL-6060s from my scrap > > pile of Johnsons before I found another one with a working final > > transistor. The first transistor I salvaged didn't have the ceramic > > ground down enough so when I was tightening it down with a loud pop > > the ceramic seperated from the copper flange. Pissed me off because it > > was still a good transistor. > > > > Had to rebuild the triplexer feeding it. I don't know what it is but I > > have seen a rash of PCB spontanious combustion in Yaesu UHF radios. > > This one was burning a hole under one of the chip inductors. I don't > > know, maybe FR4 doesnt like UHF? > > > > I also had to grab a tuning cap from the Johnson to fine match the > > transistor on UHF. > > > > Got it doing 15W on UHF and 40W on VHF. It works, just not as good as > > the original, About a dB and a half down, but it's cheap so who cares? > > I got 46W on VHF but started to have thermal fold back problems. > > > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > > > >
