deskthority

This is a bit of an unknown to me, and I was hoping somebody has seen one of these before.

I got a heck of a deal the other day, and picked up a load of old IBM mainframe equipment for less than twenty bucks. This included this 3178-2A Terminal, local controller, remote controller, and more. Not sure what I can do with it all, especially since it's missing the program floppies and the IDE/serial cables. Everything else seems to be in great shape minus that heavily screen burned tube in the display. A big plus is it still has the IBM 3174 manual, all four hundred pages in like new condition in its original fold out drawer in the local controller.





One thing I do know Is that beamspring will get some use. It had some pretty serious dirt and dust, like the other stuff I haven't cleaned yet, but it sure looked good even dirty. This was old university lab equipment and had been stored well.






Taking it apart, I immediately noticed how clean it was under the caps. My old Harris was ten times this dirty when I got it and it was basically the same age.





And it got even better once I took the remains of the contamination shield off.







This PCB hasn't even been cleaned yet.






Even the foam is still good.




It also had its maintenance library. The only thing missing was the troubleshooting guide. In the log you can see it had a couple switches fail and some loose bits in the display, but at least right now, everything looks and clicks nicely






So here's the wierd stuff about it. First, the case is completely plastic. Top plate, bottom plate, the whole deal. The model number is not one I've seen for a beamspring either. The part is 1742719, wheras I've only been able to find 1742700 1742705 and 1742720 for 3278 terminals.

Second, most of the caps are engraved and enamel filled instead of doubleshot including the front legends.




There are a few doubleshot ABS caps for the more common unaltered keys. The white in the engraved caps is totally perfect while you can seen normal yellowing in the doubleshots.




Same with the engraved brown versus the doubleshot. You can see the yellowing in one and not the other. What is the reason for that? Are they engraved PBT or something?





Lastly, I ordered a replacement for my contamination shield of .2mm black silicone. The old vulcanized rubber was pretty close to that but this should never dry out. Is the thickness in line with what other people are using? I never seemed to find any consensus on contamination shield replacements. Most people seem to forgo them entirely.

Solenoid engaged Solenoid disengaged

That's quite some equipment you bought there. Nice. I'm pretty sure all the 3278 Beamsprings we've seen here had metal cases like my 3276 and all other Beamsprings of the 32** series. I don't recall if I've ever seen engraved Beamspring keycaps like yours either but I'm not 100% sure on that. Combined with how clean the plate looks (really unbelievable) under that contamination shield I'd say you got a very unusual Beamspring.

What an incredible find!

Nice find! The engraved caps certainly are curious. The engraved front/side legends make sense, but why engrave a small version of the number in the upper right corner when, for all number keys, the engraved number is identical to the double shot number?

Congrats on your find. The engraved caps are badass.

Great find. I just bought a 3278 terminal from eBay (just the CRT) but it's in rough shape. If you want the rest of the terminal to go to a good home, I'd be interested. If your not sure what to do with the rest of the equipment, PM me and I can see if we can get it a home. There are mainframe/mini collectors that would be interested.

In terms of the keyboard, it must be a later model where they finally moved to plastics. You can see how the move in the "saving expense" direction but the internals are correct so who cares? The keyboard looks to be in great condition so congrats on the find.

The nice thing about the plastic is since it is all plastic rather then just the manual flap it all ages the same. So you don't have chipped paint on the metal and plastic which is just fine. Anywho nice find, it's always great to see a whole machine. Truly a piece of history.

Damn! Absolutely awesome get! Congrats, man! The beamer looks in great shape!

Obligatory

Sangdrax wrote: There are a few doubleshot ABS caps for the more common unaltered keys. The white in the engraved caps is totally perfect while you can seen normal yellowing in the doubleshots.

The insides of keycaps don't tend to yellow, as they're in the dark — while Retr0brighted parts will yellow in the dark, initial yellowing occurs where light reaches the plastic. It looks more like the legends were cream intentionally, although that would be unusual.

Thanks for the nice comments and info guys. For the engraved symbols, just seems like extra layers for mathematical shortcuts like on some other terminal keyboards. Seems Alt+Key for front red and Alt+Shift+Key for the top red. Haven't quite figured out the way to get the fifth symbol on some keys though.

Got the keys all clean for the most part. I wiped them down by hand since I was worried some of the paint on the engraved bits might wash out. You can get a good look at the extra symbols now. The xwhatsit controller is also coming in today so I'm looking forward to firing it up.

20 bucks, nice catch, congrats. Some collector will buy the whole system off your hand I guess.

Got a replacement contamination shield made of extremely thin silicone rubber, same thickness as the original vulcanized rubber. It works but it completely sucks. The keys are a good 30g heavier and you literally see them pull toward each other when you press a key. Looking at the original shield, I think it might have been molded with hollow bumps for the switches. It's the only way I see this not being a completely miserable experience. Unfortunately, that's almost impossible to replicate with DIY stuff. So naked switches it is!

Sangdrax wrote: [snip]

Very cool that you tried this! I've been wondering about contamination shield replacements: whether or not they'd make a difference; what materials could be used. If you try anything else, please keep us posted!

This is 100% the right material and the right thickness to replicate the original feel. The trick is how to get enough slack around the switches without molding. Probably could do it with an extra large sheet and scrunching it up a row at a time. But with that much free material wadded up, it might start catching in the springs or between the caps. Gonna take some more work to figure this problem out to be sure.