I never really thought of these older ICs having "seals", but it makes sense, in the sandwich sense. I looked at one of the Fairchild 74141s, and where the epoxy is sandwiched between the ceramic, sure enough, there's a hole in there. I thought it was a bubble, but using a high tech tool called a "needle" I poked the bad chip, and it goes a ways in. Shame. I have two other Fairchild chips to use (test first), and then I have about twenty Russian K1551D1 in stock. Fingers crossed
Shane On Fri, Jul 22, 2011 at 10:08 PM, Terry S <tschw10...@aol.com> wrote: > I'm starting to see a dramatic increase in the rate of failure on old > chips like that, both at home and in my lab at work where I have > drawers full of old TTL and CMOS -- in anti static packaging. I think > that the hermetic seal of the IC packages are breaking down over the > decades. > > Typically the legs show high rates of tarnish on the failure prone > chips, but I see that on good chips as well. I suspect the failure > rate will go up. It doesn't bode well for a lot of old equipment and > computers that employ these parts. > > Terry > > > > On Jul 22, 8:08 pm, Mimewar <mime...@gmail.com> wrote: > > I'm up to three tubes, (coding takes longer than wiring) funny thing > > is, the first 74141 (Fairchild I assume by the capitol "F") wouldn't > > display "5" or "6", so I swapped it for another, this time the "4" > > stays on all the time. I tried a third, and that one works. I have > > caps added across all ICs, and the third try worked. Is this common? > > Are the Russian 74141s better than the US? > > > > Thanks > > > > Shane > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to neonixie-l@googlegroups.com. > To unsubscribe from this group, send email to > neonixie-l+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
