MW or LW IR cameras are not exactly home shop stuff Peter. -John
============== > I had a HP 3326 which had a power supply in foldback. All the modules are > inaccessible unless you have a rather rare set of extenders anyway. The > voltmeter method quickly led me to the board and a bench supply and meter > again to the shorted cap. Very easy. Other times I've borrowed the FLIR > camera from work, also taught the new EEs that trick as well. It is a > true lifesaver on dense surface mount boards. I haven't tried the liquid > crystal sheet but it seems like an interesting idea so long as everything > is about the same height. > > > Peter > > On Mar 23, 2012, at 11:53 PM, [email protected] wrote: > >> Prior to emission or IR microscope technology, liquid crystals was how >> you found hotspots on ICs. I've done this with a goop that you dispense >> with a syringe. >> >> One trick to make this more sensitive is you bring a soldering iron >> close to the liquid crystals. Not so close as to cause a change, but >> you get them closer to the phase change point. >> >> >> -----Original Message----- >> From: Skip Withrow <[email protected]> >> Sender: [email protected] >> Date: Fri, 23 Mar 2012 21:07:45 >> To: <[email protected]> >> Reply-To: [email protected], >> Discussion of precise time and frequency measurement >> <[email protected]> >> Subject: [time-nuts] Anyone familiar with SR-620 repair? >> >> You don't need expensive test equipment to find this kind of problem. >> What >> I use is a sheet of liquid crystal film with a transition temperature >> just >> slightly above your room temperature. Just lay it on the circuit board >> and >> you can find where the power is being dissipated (even if pretty small) >> by >> watching the colors change. >> >> I think Omega Engineering sells a 8.5" x 11" sheet for about $18 if >> memory >> serves me. I have used this trick many times and it works great to find >> shorted (bypass) caps. No disconnecting anything, no milliohm meters, >> no 4 >> or 5 digit voltmeters. >> >> Regards, >> Skip Withrow >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
