> On May 26, 2024, at 10:13 AM, Leroy Jones <[email protected]> wrote: > > That kit has 19 old old plain 74XX series TTL. That keyboard draws 300 > milliamps just by itself! Those (32) 74LS273 ICs on the tube driver cards > draw > another 500 mA.
At least your fingers won't get cold. > I am seriously thinking of changing out those "LS" series chips with 74HC > versions. Much less current. What do you guys think of that idea? Sounds good but I defer to others on this. I have a single board computer that I built from a kit around 1992. An 74HC demultiplexer went bad so I rummaged through the collection and found a 74xx. I stuck it in and everything worked fine. The only difference was that that IC got MUCH hotter. All I had to do was hover my finger over it. I saw an S-100 computer back in the second half of the Seventies. The dealer had it tricked out with tons of RAM. That thing had a huge 5V power supply and got just a little warm. > On May 26, 2024, at 11:51 AM, Leroy Jones <[email protected]> wrote: > > Most of the problems were caused I think by > corroded IC pins. Took them out one by one and scraped each pin bright > again using exacto knife. A pencil eraser may be better. Those silver plated legs can get seriously corroded. Add bad sockets that seize up and you have a disaster. > A few were so badly corroded they broke right off while cleaning. Bally pinball machines where like this. The legs on the ROMs would snap right off. Fortunately, all you had to do was change a jumper or two and you could use EPROMs. Terry Bowman, KA4HJH "The Mac Doctor" https://www.astarcloseup.com "If only you could see what I've seen with your eyes."—Roy Batty, Blade Runner -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/594844BB-E674-4791-914D-E590B1DB9A14%40gmail.com.
