anyone know how long buckling spring LEDs can last?

[berserkfan]

There is this problem that has intrigued me for a long time.

I've used buckling springs for years and their LEDs never seem to die.

Are these 1980s LEDs the same as modern LEDs ie very lasting, 60000 hours?

And what happens if their LEDs die? I am a noob and very afraid of changing the LEDs for fear my clumsiness will destroy a favored keyboard. How do you guys handle such an eventuality?

[tricheboars]

dont start spreading lies about our Model M LEDs burning out. you big liar.

[1391406]

There is this problem that has intrigued me for a long time.

I've used buckling springs for years and their LEDs never seem to die.

That's a problem?

I don't know the answer, by the way.

[mich]

I was also worried about LED longevity so I bought a terminal version without LEDs. Highly recommended.

[rootwyrm]

There is this problem that has intrigued me for a long time.

I've used buckling springs for years and their LEDs never seem to die.

That's a problem?

I don't know the answer, by the way.

They do wear out but it takes literally forever and you need to cycle them to actually cause it. No, turning NumLock on and off 5 or 6 times a day will not do it. I have, however, burnt out the Scroll Lock - which I hit on average 30-40 times a day or more. It's very very uncommon though, in the extreme.

Model M LEDs come in two flavors. They come in matrix-to-sub-board and they come in wire-to-sub-board. Note the "sub board" part. It's a separate PCB mounted to the plate by double-sided tape. It's a very simple, very sturdy part and difficult to really screw up. You'll need to use a 3-5V forward voltage, and that's about the sum and substance of it. If you completely botch it, you can easily have someone make you a new LED PCB. (I offer this service on a limited basis - they're fully assembled depending on matrix or pin-wire and choice of color with direct swap in.) Hell, you can juryrig it if you want. If I had the time and funds, I would buy some Unicomps and demonstrate some very interesting mods that are possible with the LEDs these days.

[nsrexler]

LEDs are extremely long-lasting. Relatively low-powered LEDs such as those found in keyboards will last longer than the keyboard and probably even longer than you, assuming they don't sustain any physical damage.

[berserkfan]

Rootwyrm, I just saw your signature. You have worn out an IBM Model M? OMG! I didn’t think any of these would die natural deaths before 2033 or 2043!

In any case, I don’t actually understand what you said about matrix to sub board or 3-5v voltage. But is it as simple as changing a light bulb? I take out that thingy, pull out the offending LED, stick in a new led and it’s good to go?

BTW just wondering what you mean about the LEDs being cycled to cause burnout. Do you mean that keeping the LEDs on is more likely to keep them alive than turning them on and off all day? As a matter of habit, I tend to turn off numlock once numpad is not in use (the same way I turn off my lights when not in the room), but if leaving numlock on keeps it alive longer, I’m happy with that also since I like a pretty green LED anyway.

[rootwyrm]

Rootwyrm, I just saw your signature. You have worn out an IBM Model M? OMG! I didn’t think any of these would die natural deaths before 2033 or 2043!

More than one, actually. M's are not unkillable - barring abnormal wear and tear, best case you're looking at around 2 billion keystrokes estimated lifespan. IBM seriously, seriously underestimated. By the 2B number you're looking at the plate and matrix being too worn to make reliable contact, barring spring failure. I've only ever had one spring failure and it was damage related.

In any case, I don’t actually understand what you said about matrix to sub board or 3-5v voltage. But is it as simple as changing a light bulb? I take out that thingy, pull out the offending LED, stick in a new led and it’s good to go?

Not quite that simple. The matrix or wires are how the LED sub-board is connected to the main controller. They're two separate parts, so they could use the same controller PCB with a different firmware and loadout for different keyboards. (e.g. 1988 PC-AT and 3151 non-LED controllers are directly swappable both ways.)

Optimally you're looking for a 5mm green LED with 5V forward voltage. You can use down to 3V in some cases but I generally don't recommend it. Other than finding the part, it's pretty much 'disconnect PCB, remove PCB, desolder LED, solder in new LED, reinstall PCB, reconnect PCB.' Chances are you'll be able to tell which you replaced if you don't get the exact part, so I tend to recommend just doing all at the same time to guarantee consistency.

BTW just wondering what you mean about the LEDs being cycled to cause burnout. Do you mean that keeping the LEDs on is more likely to keep them alive than turning them on and off all day? As a matter of habit, I tend to turn off numlock once numpad is not in use (the same way I turn off my lights when not in the room), but if leaving numlock on keeps it alive longer, I’m happy with that also since I like a pretty green LED anyway.

I'm guessing that was a contributing factor, but there's no guarantee the ones that have failed didn't have extenuating damage as well. In fact, it's likely they did. The rated life of a typical green LED is north of 100,000 hours - or at least 11.4 years of continuous operation. Given it's IBM, presume it's rated for at least that because they just used the same LEDs as in the S/370's and S/390's. Part commonality makes for cheaper parts.
As far as a few times a day goes though, no, it doesn't have any substantial impact on the LED's life. You have to cycle constantly and frequently to have any chance at a meaningful impact. I use scroll lock as a matter of necessity (scroll lock + pgup/pgdn for console scrolling) on an exceedingly frequent basis. People cycle NumLock and CapsLock regularly and have no ill effects.