Small fix for latest batch of Apple II keyboards

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Small fix for latest batch of Apple II keyboards

Hi folks,

 

This is for those of you who are building an Apple II replacement keyboard from the unified keyboard project.

 

The good news is that once the mounting holes are adjusted, the keyboard fits great and looks and works really nice.  I will describe the problem and how to fix it with a little filing.

 

The problem is that when I measured the fit of the keyboard, I placed the board against the mounting screw holes in the case.  However, I assumed that the screws were perpendicular to the case, and did not realize that the screws were actually parallel to gravity.  When the spacers are added in, this changes (narrows) the distance between the mounting points on the keyboard.

 

 

This means the holes are not properly aligned.  The right upper slot (viewed from the point of view of a typist at the keyboard) is OK.  The two left-side slots and the right lower slot are off.  Of course they will be adjusted in the next revision.

 

The first step is to mount the standoffs in the holes, and position the keyboard so the keys are properly centered in the case.  Then use a sharpie to mark the areas where the screws need to be positioned.

 

 

Next, file away the PCB material to make room for the screws:

 

 

 

 

Now the keyboard can be mounted to the spacers:

 

 

 

The power light here looks red, but that's a camera artifact.  The power light is actually an amber color.  Here's a keyboard test

 

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By the way, those spacers are

By the way, those spacers are 5/8" long 6-32 hexagonal standoffs, male at one end (screwing into the case) and female at the other end (for mounting the keyboard).

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Note, this keyboard used the

Note, this keyboard used the Futaba keys.  The Cherry keys are much shorter, and spacers can be omitted so that the keyboard will mount without adjustments.

 

That means that to fit both key types, the slots need to be turned vertically instead of horizontally, to accommodate both heights.  The next revision will be fixed to fit with either switch type without any filing.

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dfnr2 wrote:Note, this
dfnr2 wrote:

Note, this keyboard used the Futaba keys.  The Cherry keys are much shorter, and spacers can be omitted so that the keyboard will mount without adjustments.

Actually that might not be right.  The Cherry MX keys are shorter, but a shorter spacer may still be needed, and the above procedure still applies.  Again, this will be fixed in future revs.

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dfnr2 wrote:dfnr2 wrote:Note,
dfnr2 wrote:
dfnr2 wrote:

Note, this keyboard used the Futaba keys.  The Cherry keys are much shorter, and spacers can be omitted so that the keyboard will mount without adjustments.

Actually that might not be right.  The Cherry MX keys are shorter, but a shorter spacer may still be needed, and the above procedure still applies.  Again, this will

 

Please inform me when you have the design sorted. 

 

I'm curious: Did you use a grain of rice bulb for the power key, or did you go the LED route? The originals has a grain of rice microbulb, which is an incandescent lamp. 

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Timelord wrote:I'm curious:
Timelord wrote:
I'm curious: Did you use a grain of rice bulb for the power key, or did you go the LED route? The originals has a grain of rice microbulb, which is an incandescent lamp. 

 I just sent off an order for the new revision, which incorporates a lot of fixes and cleanups:

  • improves the stabilizer function (for futaba switches)
  • fixes apple II case alignment
  • Adds some clearance about pads that are prone to short on some PCBs
  • Design for Manufacture improvements for surface mount components on the keyboard

The footprints are designed to accommodate 3mm LEDs since they are widely accessible and available in various color options (I think the range would be different temperatures of white and amber.)  But there's no reason why a rice grain lamp could not also be used.

 

 

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