Over the last week or so there have been many questions about how a HHKB Pro 2 is different than a Realforce board. Seeing that we did not have a article showing the HHKB Pro 2 opened up and I needed to clean mine any ways I decided to take some pictures of the inside of my HHKB Pro 2. While I had it opened up I took about 30 pictures of the verious aspects of the HHKB Pro 2 that make it different than a Realforce board. For a refreasher of what is inside a Realforce board take look at Realforce 87U Opened Up that ripster did. Mostly ripster was investigating the rubber domes of the 87U versas how it was built so there are no pictures of some of the features that make it different. But there is enough there to see what we will be talking about.

The first thing you will notice when you open the HHKB Pro 2 up is that it does not have a metal plate. The picture below shows it when first opened from the bottom.

No metal plate but you will find 17 screws holding the PCB to the top of the keyboard.

After you get all those screws out and separate the PCB from the top you will have the PCB with the rubber domes attached. I'm not going to show that picture here but will post it in the discussion section for those that are interested. The PCB of the HHKB and the Realforce are very similar. What makes them different is how the keys are mounted. Here is a picture of the HHKB from the bottom after the PCB has been removed.

As you can see the key slider housing is actually part of the top keyboard housing. In a Realforce board the keys are mounted to a metal plate and then the top frame goes over that.

Here is the top of the keyboard with all the keys removed.

You will note that I have removed one of the sliders from the keyboard top. Some things to notice when looking at the picture above.

[*] The slider housing is moulded into the keyboard top. On a Realforce board they are separate units that are then mounted into a metal plate.
[*] The enter key and left shift key has the stabilisers mounted on the underside of the keyboard top. And they do not attach to the actual key cap. So removing those keys are easy and trouble free.
[*] Check out the space bar mounts at the bottom. The stabiliser mount housing are separate units and are not moulded into the keyboard top like the switch housings are. Note the rubber pads next to the stabiliser mounts when you press the space bar down and you bottom it out you are actually hitting those instead of bottoming out the dome. Those bumpers really knock out space bar bottom out noise.
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One last picture since this subject has come up lately as well. The famous Topre Fart .

If you look closely at where the dome sits on the PCB you will see some small vent channels moulded into the dome. There are 4 of these vents around the dome. These vents are supposed to prevent the Topre's from Farting or sticking. I will post a picture of the bottom side of the dome in the discussion section.

So now we know what the difference is between a Realforce board and the HHKB Pro 2. It is primarily how the keys are mounted to the PCB. On the Realforce they are plate mounted then the PCB is screwed into the plate. On the HHKB Pro 2 the switch housing is moulded into the keyboard top which then has the PCB screwed to it. But how does this difference affect key feel, key sound, and quality. Key feel does not seem to be affected at all both boards feel pretty much identical to me. Key sound though is different on the Realforce the keys have a deeper tone to them when bottoming them out. On the HHKB Pro 2 the keys are a little higher pitched and don't have as much of the Thunk sound that the Realforces have. Quality is a subjective matter but I really don't think that there is that much of a difference. I think PFU chose plastic for the key mounts in the HHKB Pro due to weight. I think they wanted a light weight board that you could carry around and use on all of your computers. Realforce on the other hand wanted a heavy board that would be attached to a particular computer and stay there.

Now for pictures of the inside of the board.

A close of how that cable is attached that you will need to remove if you open yours up.

Their is a ridge on the male connector that you can use to remove the cable. I used a screw driver placed in that gap between the housing of the socket and the ridge. Then just gently turning my screw driver removed the cable with out damage. Don't pull on those wires surface mount female connectors like used here are not as robust as through hole connectors so be gentle and you  will be ok. Oh also do you see that wire protector it will move around before you can put your board back together that will need to be about that far away from than end of the wiring if it moves down the case will not close.

Here we have the domes sitting on top of the PCB:

Pretty much just like a Realforce board.

Stabiliser under the enter key or left shift. Sorry but I don't remember which one I took the picture of.


One side of the space bar stabiliser:

Ok just a few more and I'm done.

Inside the key housing with the plunger/slider removed


The plunger


A collapsed and bottomed out dome:

Amazing work! Looking at your last photo it really shows the "soft landing". Nice to see all that squeak-resistant goop underneath the board on the stabilizer.

You've also got brass ones tearing it down like that

Nice nice, and yeah keep us posted.

When I was swapping keytops, I noticed how clean everything was. No switch mounted pcb to clean around or anything like that. Truly designed to long term in mind

Cool that's nice to know. I almost got one of those on Yahoo Japan last week but some one snipped me . Who ever got it got it for a good price though. I keep thinking if I'm going to be buying boards on Yahoo Japan I may have to write myself some snipe software that can work with the buying services. But then I think na I'm not going to be buying enough to justify the effort. And I've learned my lesson I just set my max bid high enough that I don't get sniped and I don't place it until the last day as close to the end of the bid as I can.

Those key layout pictures on the back of the board were not put there by PFU but rather by whoever you bought that board from.  I remember seeing another member posting those pictures here for that purpose sometime last year.

EDIT: Found it and thanks for reminding me about that picture, *saves*

By the way, are you sure the pictures are supposed to be on the back of the keyboard to show the layout? Why don't I have those pictures? lol

The answer is a couple of posts above yours, I guess you missed it

Those key layout pictures on the back of the board were not put there by PFU but rather by whoever you bought that board from.  I remember seeing another member posting those pictures here for that purpose sometime last year.

Those key layout pictures on the back of the board were not put there by PFU but rather by whoever you bought that board from.  I remember seeing another member posting those pictures here for that purpose sometime last year.

EDIT: Found it and thanks for reminding me about that picture, *saves*

And wouldn't you know I got my HHKB Pro 2 from megarat. I have to say he did a good job putting that layout picture on the back. It really does look as if it came on the board that way. But now that you have pointed it out it feels like it is made of standard paper and I would think that if PFU did put that on there it would have been made of something a little more sturdy.

* the "wire protector" is probably metal and a therefore a ferrite for EMI. Pretty common - my M4-1 and NeXT have them too.

Your probably right it did not feel like plastic when I moved it around so I could close my case. Boy let me tell you I was worried there for a bit that I had screwed something up when the case would not close. It took me a while to calm down and figure out what it was and it was a big relief when I finally figured that out.

* Big ABS stamp on the case (the 87U case is also ABS plastic).  I'm a big fan of ABS but watch the white cases under sunlight.  Might be susceptible to yellowing.  Hopefully the additives have improved in the last 20 years.

You know something when I was taking that picture and saw that big ABS stamped into the case my first thought was I bet ripster will see that and go "Ah Ha I knew that case had to be ABS" so I left it there for you to point out. :bounce:

* I gotta measure the spacebar activation force.  Get a handful of springs like that and you may be able to mod away the board easily for stiffer keyboard fans.

I was thinking the same thing. Where can I find some springs like this so I can try it on some other keys. I don't think it adds much to the activation force but it does make the space bar bounce back faster than one of the other keys. Which is what I really think it is for. That space bar has to pick up the weight of the stabiliser. The other keys with stabilisers don't feel as if they bounce back quite as fast as a normal key but the stabilisers on them are not as big as that one on the space bar so no spring. I wonder if adding one would make them feel more bouncy.

* The rubber material is EPT (ethylene-propylene-terpolymer) according to the patent.  It's used in everything from radiator hoses to athletic shoes.  Have no idea if anyone else uses it in their rubber dome boards but I kinda doubt it's all that special - the spring does add SOME force (5g or so) and that does make the key feel unique.

Cool I knew it was different than what is used in most rubber domes. Every one I've opened up uses the same stuff used in the Keytronic that looks like this:

* Glad you highlighted the key sliders.  I think they add a lot to the keyfeel as well.

What is left to do though is to take apart one that is mounted in a metal plate. But I think they are the same and the only difference is that the housing is a separate moulding but still would like to verify it. Some of the pictures I've seen of older Topre switches look like they may be different I guess I will find out as I have secured a few of them.

The Pro and Pro 2 are so nearly identical, that I personally wouldn't bother.
On the other hand, it's your collection, not mine.  

The only difference between the two, as far as I can tell, is the USB ports they added to the Pro 2.  

Can anyone confirm that's the only difference?

I mostly was going to get that Pro version because it was such a good price and I would not mind having one (BTW It went for something like 7,250 yen).

Your last question is really the main reason I want one. To have a complete collection if I can get them at a reasonable price. So questions like that can be answered and documented here. I would really love to see the GeekHack review and modifications section be the go to place for keyboard documentation. As it is now we have to find this stuff over on Japanese or Korean web sites. But to get that depth of coverage someone has to acquire these boards and take them apart and then write something up so others can find it. For now I'm trying to do that for the Topre boards. For instance there is praticly zero information on the net about one of the boards I have comming the NISSHO Electronics KB106DE even though there are a few of them floating around.

OK, I just swapped the spacebar spring onto the F key.  Good news and bad news.  It is a nice ideal 60g (for you Model F and Selectric fans).  Bad news is that the key feels almost linear now.  I wouldn't recommend paying $1200 for a custom run of springs but if you happen to work in a spring factory they shouldn't be hard to replicate.

Don't think I would like a 60g Topre. Definitely don't want it linear.

No rubber baby buggy bumpers on the 87U.

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Wonder if they put those bumpers on the HHKB to eliminate plastic on plastic clacking. Those bumper would change the sound of bottoming out I would think. The space bar looks the same as the HHKB again I wonder if you could just stick some bumpers in there but how would that affect the sound/feel hmm...

Digital crop of a previous 87U pic:

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They are like you thought - individual plastic keyholders mounted on a metal plate.   The metal plate probably doesn't change the key feel as much as sound and obviously the weight of the keyboard.

The look to be exactly like the HHKB even down to those keys that hold the dome in the right place in the housing.

I love ABS!!!  Any self respecting LEGO fan would.  They are entirely made of ABS.   Chloe didn't seem to like ABS but I sure do - I haven't broken a LEGO yet!

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From Wikipedia:


There are 62 LEGO bricks for every living person on earth.  Be sure to play nice and share.

Did you build that. It is so cool. I'm really trying to get my son into LEGO bricks but I think I'm going to have to let him get a little older. Right now he is having to much fun with that magnifying glass I gave him.

One more question are those rivets I'm seeing in those pictures of the 87U? what are they used for? I thought the metal plate was one piece. Oh wait I bet those are where the screws go right.

That Pro I was bidding on at Yahoo Japan had a PS/2 connector. But then again it was built in 97. I wonder if there were different revisions of the original Pro.

If the one you bid on was from 1997, it probably was an (original) HHKB, not a Pro, which would mean it was a rubber dome board.
   
According to Wikipedia, the original HHKB was the only model existing before 1999, when the HHKB Lite was released.  The Moonlight Cafe site has a 2003 release date for the first HHKB Professional.

Forgot that was there. Went and took a look that thing needs a rewrite. It has a lot of good information but needs to be rearranged and completed. I guess I need to go and fix that.