NEC APC-H412 Problems

[rich1051414]

I found a NEC APC-H412 at the recycling center recently, but I have been having some problems with it. Due to a 90 degree bend in the PS/2 connector, I own no PC's which I can actually get the connector to connect to. Also, I cannot get it to function at all with a passive PS/2 to USB adapter.
However, I can get it to work with my trusty active adapter(The Y connector variety), HOWEVER, it has been having problems. The keys stick and bugs out periodically, which I think has to do with the rollover. What kind of rollover does this keyboard have, and does it have problems releasing keys if too many keys are pressed at once?
Basically, I am trying to figure out if it is the adapter causing the problems, or an inherent problem with the keyboard.

I really want to get this keyboard fully functioning. The NEC blue switches have quite the satisfying feel, which feel somewhere between cherry blue and alps blue, but the sound is like model M lite(if that makes sense). Kind of pingy and sings when you go to town on it, but not nearly as loud, the click volume is similar to alps.
It is fine for typing as you would rarely press multiple keys at once, but the keyboard completely glitches out when doing some keyboard shortcuts or attempting to game, which will cause it to be retired to the shelf of dust if I cannot correct it.

Here are some relevant images if it matters:

[Polecat]

I found a NEC APC-H412 at the recycling center recently, but I have been having some problems with it. Due to a 90 degree bend in the PS/2 connector, I own no PC's which I can actually get the connector to connect to. Also, I cannot get it to function at all with a passive PS/2 to USB adapter.
However, I can get it to work with my trusty active adapter(The Y connector variety), HOWEVER, it has been having problems. The keys stick and bugs out periodically, which I think has to do with the rollover. What kind of rollover does this keyboard have, and does it have problems releasing keys if too many keys are pressed at once?
Basically, I am trying to figure out if it is the adapter causing the problems, or an inherent problem with the keyboard.

I really want to get this keyboard fully functioning. The NEC blue switches have quite the satisfying feel, which feel somewhere between cherry blue and alps blue, but the sound is like model M lite(if that makes sense). Kind of pingy and sings when you go to town on it, but not nearly as loud, the click volume is similar to alps.
It is fine for typing as you would rarely press multiple keys at once, but the keyboard completely glitches out when doing some keyboard shortcuts or attempting to game, which will cause it to be retired to the shelf of dust if I cannot correct it.

Here are some relevant images if it matters:

Nice find! That's *exactly* what my Multitech/Acer KB-101A does on a converter. I'm still trying to figure out why, and I will eventually, but for now I can tell you several things I've tried that didn't work. I also have the same model NEC here, so I can try mine to see if it acts the same.

My Acer works perfectly connected directly to a PS/2 motherboard. If that's an option for you, a PS/2 extension cable might be all you need, or you can replace the right angle cable with a straight one.

I've tried two different converters for the Acer - a blue cube, and a dongle-type (Radio Shack), and it does the same thing on both. My Montereys and Northgates (and others) work fine through the same converters. I tried connecting the converters to a powered hub, no change. I replaced the electrolytic caps on the PC board, no change. I tried 4.7K pull-up resistors on the clock and data lines, no change. I don't think it's a rollover problem, but it's remotely possible.

A passive USB adapter will work only on boards with internal USB provisions. USB didn't come out until 1996-1997, so no keyboard earlier than that will work with a passive USB adapter. But a passive AT to PS/2 or PS/2 to AT adapter will work on any AT-compatible board since AT and PS/2 keyboard protocols are the same except for the connector.

I'll try my NEC on my converters, and I'll update this thread once I get the Acer to work correctly on USB.

[dokyun]

I use mine with some tmk firmware to convert it to USB and it works reasonably well. It tends to drop the connection sometimes which, I always figured might be because I don't have a pull-up resistor on my teensy, but I've never looked too deep into the problem.

[juryduty]

FWIW I had the same problem with my H412. It would work with both the inline (Belkin) PS/2 converter and the blue cube but be pretty much unusable due to dropped keystrokes and repeat key weirdness. It does work fine on PS/2 directly. You could try one of those "breakout" cables to get around the PS/2 fit: http://a.co/geTFVFI

[rich1051414]

Thanks. I will, only by a brand other than the god awful startech.

[Polecat]

I'll try my NEC on my converters, and I'll update this thread once I get the Acer to work correctly on USB.

Strangely, my NEC is working fine on the Radio Shack USB converter. Typing on it now.

[rich1051414]

I got my ps2 extension cable in today, and so far so good. Shortcuts that weren't working before are working now, so it seems to be fixed.

HOWEVER, key repeat rate is slower than every other keyboard I own. Strange. I didn't think it had anything to do with the keyboard. Maybe my pc just treats the PS/2 port slightly different. Either way, my problem seems to be solved now.

FYI, I went with a Tripp-lite PS/2 extension cable(Tripp-lite has never let me down on anything) so the 90 degree bend doesn't matter anymore. Works great. I have no desire to ever use a ps/2 mouse, so there is no reason for me to get a breakout cable.

Whose stupid idea was it to make the ps/2 port have a 90 degree bend anyway xD

[rich1051414]

By the way, are these keycaps ABS? They don't feel right. I think they are POM. I know the double shot for the legends are light gray, which is different, but the keys are so slick they are actually grippy. I kind of like it, its feels nicer than textured, and since I don't actually slip on them like worn out ABS keys, there is no downside. Are they POM?

Beyond that, now that I have actually got to type on it a while(A days worth of programming), my opinion has changed. I don't like the nec blue ovals

The particular tactility of them lends to an unsatisfying typing experience after a while. I don't know if it is because the keyboard is used, but they are simply too uncompromising when pressing them off axis. It reminds me a bit of Mitsumi switches, and that is NOT a good thing.

They aren't even in the same ballpark as my favorite antique keyboard, a chicony 5191 with Futaba MA clicky switches, followed closely by the original AEK with orange alps. Yes, I do rate the Futaba ma switches higher than orange alps. The only thing about the chicony board I hate is the 1u backspace. Thankfully, I rarely actually have typing errors on the keyboard.

Maybe if I come across another NEC one day, I will get them a shot again, but as far as them being the 'best switch', that is a big NOPE from me. I'll take cherry blues before this keyboard. All because when you press them off axis, the weight doubles or triples, and almost feels crunchy. Terrible feeling. Maybe if I had better form it would be different. It very well could be because the keyboard is worn out as well. Either way, I won't be using it

[Polecat]

By the way, are these keycaps ABS? They don't feel right. I think they are POM. I know the double shot for the legends are light gray, which is different, but the keys are so slick they are actually grippy. I kind of like it, its feels nicer than textured, and since I don't actually slip on them like worn out ABS keys, there is no downside. Are they POM?

Beyond that, now that I have actually got to type on it a while(A days worth of programming), my opinion has changed. I don't like the nec blue ovals

The particular tactility of them lends to an unsatisfying typing experience after a while. I don't know if it is because the keyboard is used, but they are simply too uncompromising when pressing them off axis. It reminds me a but of Mitsumi switches, and that is NOT a good thing.

They aren't even in the same ballpark as my favorite antique keyboard, a chicony 5191 with Futaba MA clicky switches, followed closely by the original AEK with orange alps. Yes, I do rate the Futaba ma switches higher than orange alps. The only thing about the chicony board I hate is the 1u backspace. Thankfully, I rarely actually have typing errors on the keyboard.

Maybe if I come across another NEC one day, I will get them a shot again, but as far as them being the 'best switch', that is a big NOPE from me. I'll take cherry blues before this keyboard. All because when you press them off axis, the weight doubles or triples, and almost feels crunchy. Terrible feeling. Maybe if I had better form it would be different.

The right angle plug keyboards usually came with computers having the jack on the front (Leading Edge, etc.). I don't know which computer(s) this NEC board came with, but I'd be willing to bet it was an OEM keyboard that came with a particular model or models, rather than one that was sold separately in computer stores. We need those old computer magazine ads!

I don't know how to identify the plastic, but my NEC is considerably more yellowed than yours, case and caps. It also has the gray-lettered double shots. I'm back to typing on my blue Alps Laser, so the NEC didn't do much for me either. I only saved it because it was "interesting". I basically have no feeling in my fingertips, so it must be the switches rather than the caps in my case.

[rich1051414]

Kind of difficult to see how yellowed the keyboard and keys are due to my horrible lighting conditions, but the Y adapter in the first picture is true white, for reference. It is definitely very mildly yellowed given it's age, and the keyboard does not appear to be heavily used at all, but that doesn't really mean a whole lot.

I was just going to assume for now that the board is simply wore out, as my experience seems to contradict other people's opinion on the board. I just can't do this one unfortunately. Not for me. So I as well will just retire it to the shelf of interesting keyboards.

[juryduty]

Yeah they are kind of hit and miss. Just like alps the condition seems to be key. I have 2, one is in pretty good shape and is usable, the other has the same problems you mention. Lube on the switches does not seem to help, but a drop of lube where each stabilizer wire contacts the plate does help quite a bit with the larger keys off-axis. Someday we'll find a NIB/NOS one and we will get to see what they're like in their original form. . I like them because they are very quiet.

[rich1051414]

Yeah they are kind of hit and miss. Just like alps the condition seems to be key. I have 2, one is in pretty good shape and is usable, the other has the same problems you mention. Lube on the switches does not seem to help, but a drop of lube where each stabilizer wire contacts the plate does help quite a bit with the larger keys off-axis. Someday we'll find a NIB/NOS one and we will get to see what they're like in their original form. . I like them because they are very quiet.

Yeah, I tried with a light weight penetrating lube that goes on wet but stays on dry, as it seems to be the safest lube for these strange boards. Other lubes seem to commonly do more damage than they help. However, even though it did help with some of the keys that were particularly bindy, it didn't really help at all with the overall feel of them. I don't like the idea of using any sort of grease lube in any switch.

[Polecat]

Nice find! That's *exactly* what my Multitech/Acer KB-101A does on a converter. I'm still trying to figure out why, and I will eventually, but for now I can tell you several things I've tried that didn't work. I also have the same model NEC here, so I can try mine to see if it acts the same.

My Acer works perfectly connected directly to a PS/2 motherboard. If that's an option for you, a PS/2 extension cable might be all you need, or you can replace the right angle cable with a straight one.

I've tried two different converters for the Acer - a blue cube, and a dongle-type (Radio Shack), and it does the same thing on both. My Montereys and Northgates (and others) work fine through the same converters. I tried connecting the converters to a powered hub, no change. I replaced the electrolytic caps on the PC board, no change. I tried 4.7K pull-up resistors on the clock and data lines, no change. I don't think it's a rollover problem, but it's remotely possible.

A passive USB adapter will work only on boards with internal USB provisions. USB didn't come out until 1996-1997, so no keyboard earlier than that will work with a passive USB adapter. But a passive AT to PS/2 or PS/2 to AT adapter will work on any AT-compatible board since AT and PS/2 keyboard protocols are the same except for the connector.

I'll try my NEC on my converters, and I'll update this thread once I get the Acer to work correctly on USB.

Promised update--I ordered a Soarer's Converter from our friend Orihalcon, and the Acer KB-101A works perfectly (on the Mac) using that converter. Plug in and go. Again the Acer did not work right with a blue cube or with a Radio Shack dongle-type converter, exhibiting symptoms very much like rich1051414's NEC with both of those. Two thumbs up for Soarer's Converter and Orihalcon!

[rich1051414]

Yeah, also, my Siig minitouch also has the lost keystroke and sticky keys issues with most converters. However, I now run off a native ps/2 port whenever possible, since you can still buy motherboards with support.

I think the issue is mostly with older keyboards when the AT standard was not the universal standard yet. I am not sure, but it might have to do with the microcontroller, as I think the microcontroller is the same exact one for all my keyboards that behave strangely, and they are all around the same age.

Sorry, but I am not a mac fan, but I guess soarers is a solution for them. I prefer options But this forum is about keyboards, not pcmasterrace talk, lol.

I'll remember this though in the future if native PS/2 is no longer an option. Already, native ps/2 has legacy support in windows, and behaves differently than USB keyboards, particularly when it comes to settings regarding the speed of key repeating.

[seebart]

Sorry, but I am not a mac fan, but I guess soarers is a solution for them. I prefer options But this forum is about keyboards, not pcmasterrace talk, lol.

Soarers converter has nothing to do with mac, I've never used a mac and use soarers converter all the time. The description of your NEC APC-H412 problems sound like they may come from the keyboard itself having age-related problems, electrical and or mechanical.

[rich1051414]

Sorry, but I am not a mac fan, but I guess soarers is a solution for them. I prefer options But this forum is about keyboards, not pcmasterrace talk, lol.

Soarers converter has nothing to do with mac, I've never used a mac and use soarers converter all the time. The description of your NEC APC-H412 problems sound like they may come from the keyboard itself having age-related problems, electrical and or mechanical.

It functions perfectly on native ps/2, but I guess it is possible.

[Polecat]

Sorry, but I am not a mac fan, but I guess soarers is a solution for them. I prefer options But this forum is about keyboards, not pcmasterrace talk, lol.

Soarers converter has nothing to do with mac, I've never used a mac and use soarers converter all the time. The description of your NEC APC-H412 problems sound like they may come from the keyboard itself having age-related problems, electrical and or mechanical.

It functions perfectly on native ps/2, but I guess it is possible.

My Acer works perfectly on native PS/2. My Monterey (and others including my NEC) work perfectly on the same Mac with the same blue cube and Radio Shack converters that don't work on the Acer. I replaced the electrolytic cap (only one) in the Acer with no change. Likewise with pull up resistors. I don't believe it's an age-related thing, but I can't prove that. I suspected a power (current draw) issue, but running direct or through a powered USB hub doesn't make a difference.

Correct that Soarer's Converter has nothing to do with a Mac, other than the Mac being the only computer that doesn't have a PS/2 port in my case. But if (speculation warning to dissuade the Wrath of Beardsmore) it works as well with other "problem" keyboards on a USB PC as it does with the Acer on my Mac it's a good solution all around.

very late edit: Orihalcon's Soarers did, and continues to work on every AT and PS/2 keyboard I've tried it on. Occasionally (as in maybe once a month) on computers that never get rebooted it may need a reset, but that's a trivial complaint.