I have used a similar idea from PCB-video. It's called the RAID tool and is basically a molded plexiglass fixture with prisms forming both sides. Look down into one and shine the light down into the other. It's far from the ERSA scope but it costs only $35.00. In regards to Richard's idea, Edmund also has very small glass prisms with a reflective coating on the hypotenuse. Someday in my spare time (HA!) I want to fool with these for a low budget ERSA scope. John Thorup > -----Original Message----- > From: Richard Tilbrook [SMTP:[log in to unmask]] > Sent: Monday, June 05, 2000 7:12 AM > To: [log in to unmask] > Subject: Re: [TN] Other visual tests under a BGA possible? > > Well, while we're sharing cunning plans, I'll blurt out mine before I > apply for the > patent (only kidding). > > This one's labour intensive, and I haven't tried it myself yet, so please > don't > send me the Blu Peter award for the worst idea, but . . . > > - get a 45 degree front coated mirror, Edmund Scientific do one 5x5mm, > someone else > might do one smaller > - place the mirror close to the BGA / heel joint / whatever > - apply light from that side > - look down an inspection microscope (perpendicular to the board) at the > mirror > - cross fingers and see if there is any visibility > > Obviously if you're going to be spending a lot of time looking under > things this > isn't the way to do it, but for occasional looks, seeing whats going on, > someone > out there might find this a useful and cheap alternative. > > Of course, you have to treat front coated mirrors really nicely too, or > they just > become prisms. > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c > ############################################################## > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in > the body: > To subscribe: SUBSCRIBE TECHNET <your full name> > To unsubscribe: SIGNOFF TECHNET > ############################################################## > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information. > If you need assistance - contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################