[Halld-cal] 2500 volt capacitors

[Paul Smith]

On Jul 8, 2010, at 9:53 AM, Fernando J. Barbosa wrote:

>> 
>>  
> Is the metalization you refer to SnPb? If it is, it will most likely get better once the board is re-flow soldered in the oven as sharp edges will decrease.

According to the data sheet, Ni and Sn.

>> 
>>  
> I am glad the 1B31 will do the job. You can remove the solder mask from under the components, or partly, to provide more clearance under the components and make it easier for the 1B31 to get under.

Yes, I'm removing solder mask underneath (and rounding pad corners) per this app note from Johanson:

http://www.johansondielectrics.com/images/stories/tech-notes/application/JDI_ARC-Design-Observations_2006-03.pdf

> 
> 
> I agree that "burn-in" of the caps is not practical but you might consider a procedure to have the boards very well cleaned after assembly, followed by a 30 minute oven dry cycle at 50-70C or in a purged nitrogen atmosphere for a week and immediately followed by application of the conformal coating.


I have been baking before coating, and plan for the contract assembler to do so as well.

Paul