Hi Peter, You are right, 'the reason why one drills up into the central ball of a BGA to place a T/C, is because it's these central contacts that generally suffer from insufficient heating owing to the shading effect of the overlying body of the component.' The question I answered was how to determine the temperature of a component body. This will be even more important given the idiotic drive towards lead-free solders, when solder reflow temperatures need to be higher and thus component temperatures as well. Thus, knowing the component temperatures will be even more important than now. Werner Engelmaier --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------