I'm curious to know how you would repair the missing conductor of an isotherm spoke connection and not compromise the drilled hole connection? Dave Rooke Circo Craft - Pointe Claire _______ reply separator ________ >Dave Hillman posted: >> What is the effect, if any, of >> one of the four "spokes" going from a grounded pad to the clad area >> being broken. I've been under the opinion that one of the four >> "spokes" being disrupted would not cause significant reduction in the >> electrical or thermal properties of the grounded through. Would you >> gentlemen please give your opinion of the effect of one spoke being >> damaged and whether you feel a repair is needed." >> >> >> Dave Hillman >> Rockwell Collins >> [log in to unmask] >Dave, > The effect of one spoke being broken is the loss of 25% of the >copper crossectional area of the path to that via. This would create >additional power loss in the rest of the spokes and would increase the >temperature of the copper and the board at that point. The result is some >loss of the reliability of that particular hole and some (probably very >small) increase in the total voltage drop in that net. Whether or not to >repair the missing spoke is impossible to answer without knowing the end >use (ie, required MTBF of the board) and the built in redundancy (ie, how >many holes can fail before the whole board is a failure). Here, where most >of work goes into far away and unrepairable locations and we do >one-of-a-kind stuff, we'd repair it. > Howard Feldmesser > Johns Hopkins University Applied Physics Laboratory > > >*************************************************************************** >* TechNet mail list is provided as a service by IPC using SmartList v3.05 * >*************************************************************************** >* To unsubscribe from this list at any time, send a message to: * >* [log in to unmask] with <subject: unsubscribe> and no text. * >*************************************************************************** > > > *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************