Retro-Retro Computing Repairs

[Slob]

i built a few boards about 20 years ago that demo'ed the 8008 and the 8080 with scrolling descriptions of the chips. I pulled these out of storage to look at while I was building new 4004 and 4040 hardware. They didn't seem to want to reset anymore. It turned out that although my wire-wrapping held after almost 20 years, the #$%#^$ cheap-az surplus pushbuttons didn't work anymore! I replaced them, and we are good again. So, this is a "retro-retro-computing" fix, I guess. Who could believe that simple board-mounted pushbutton switches could go bad? These weren't even from eBay. I had some free time back then and built a few more of these and sold them on eBay in maybe 2000 or so. If anybody who bought these is reading...IT'S THE PUSH BUTTONS!

Another problem I've run into is that my UVEPROM eraser is not erasing anymore. I have one of those incredibly cheap and dangerous models that you see on eBay, but it's at least 18 years old. I'm going to assume that the tube got "old", not from number of running hours, but from hours of existence! It seems very, very blotchy and the color is definitely not what it once was. I've ordered another tube (this time, a name brand), and we will see how it goes, if I don't kill myself. Those Chinese UVEPROM erasers are Undertakers Laboratories approved!

 

[deathshadow]

I've had a number of older projects where cheap bulk buttons and keypads have gone bits-up face-down. I've actually said to hell with it and started using knockoffs of cherry blue's as replacements if they can be fit into the existing locations.

Since even if they're a knockoff like an outemu or Gateron, being based on the cherry switch design you know they're gonna be rock solid for "infrequent" use projects like these for .. well, ever?

... and it's not like they're prohibitively expensive. Packs of 10 will usually run you under a buck-fifty off e-fence.

Though with my EWI knockoff project I just splurged and dropped a buck a pop on two dozen genuine Cherry MX Speed Silvers. Being a musical instrument that's gonna be some high duty cycle stuff and I wanted minimal travel/force. I'm ditching the whole capacitive touch BS, it's cute but too fragile.

 

[glitch]

Argh, don't you hate that?! That was a lesson I ended up learning some time in college. I recently almost repeated it with a big lot of 8-position DIP switches from the MIT Flea. Fortunately I caught it on the first project I used one with, but they were labeled backwards, such that having the DIP switch in the ON position meant the contacts were open. And, not all of them were like that, so I guess it was a manufacturing oops. I labeled them and passed them off to someone else.

Nice work on the boards, by the way! I'm pretty sure I'd seen those before, possibly when the others were listed on eBay.