I would like to see the gauss measurements that start affecting the on-off state of a transistor my self or that assure without a doubt that would not affect them at all. So far I have found not a thing. Even if someone from a company states that are not affected them still does not prove it 100%. How many products claim one thing or another and fail in real life. One way that I would unscientifically prove it, is to have every type of memory chip, program them, place them in a magnetic field and check their programs again. It may turn out to be an old wives tale that memory chips are not affected by magnetic fields and someone may get burned. In the mean time I would err on the cautious side. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of George Patrick Sent: Wednesday, March 23, 2005 5:05 PM To: [log in to unmask] Subject: Re: [TN] Magnetic Screwdrivers Ramon: I'd appreciate that. It would be a help to see the gauss measurement where the charges start being affected. As an "old-timer" tech myself, I distrust "somebody said" things. I have been burned too many times by "old-wives-tales" that turned out to have no basis in fact :) -- George Patrick Tektronix, Inc. Central Engineering, PCB Design Group P.O. Box 500, M/S 39-512 Beaverton, OR 97077-0001 Phone: 503-627-5272 Fax: 503-627-5587 http://www.tektronix.com http://www.pcb-designer.com It's my opinion, not Tektronix' -----Original Message----- From: Dehoyos, Ramon [mailto:[log in to unmask]] Sent: Wednesday, March 23, 2005 13:42 To: TechNet E-Mail Forum; Patrick, George H Subject: RE: [TN] Magnetic Screwdrivers All our product uses SS hardware so magnetized screw drivers do not help, but one of our old timers techs that deals with testing of boards said: Magnetized screw drivers scramble the programs. So it is not about erasing the program but altering it. One or many transistors that switches from high to low will alter the program. It may not happen all the time, but if it happened one time in a hundred it would be one too many. I tried to get something in writing about this possibility from big companies that build EPROMs. Some did not response and one said that the fellow that did this kind of experiments retired. When ever the right time comes, I will do some experiments and get back with you. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of George Patrick Sent: Wednesday, March 23, 2005 4:24 PM To: [log in to unmask] Subject: Re: [TN] Magnetic Screwdrivers OK. I have looked at the postings. I still see nothing that would lead me to believe that a weak magnetic field could erase an EPROM. Last time I heard, EPROMS were programmed by electrical charge (the programming cells are capacitors) and a weak magnetic field shouldn't induce enough current to change that charge. I would buy an High power X-ray erasing them, the current induced by that could be enough to change the charge and do the job. I just don't see it happening from the gauss produced by a magnetized screwdriver tip. I would still like to see any current references to the contrary if I am wrong, though :) -- George Patrick Tektronix, Inc. Central Engineering, PCB Design Group P.O. Box 500, M/S 39-512 Beaverton, OR 97077-0001 Phone: 503-627-5272 Fax: 503-627-5587 http://www.tektronix.com http://www.pcb-designer.com It's my opinion, not Tektronix' -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken Sent: Wednesday, March 23, 2005 12:45 To: [log in to unmask] Subject: Re: [TN] Magnetic Screwdrivers I would check the TechNet archives. There was a pretty extensive discussion on this subject a few months ago. KennyB --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------