New Apple 2 Keyboard replacement

63 posts / 0 new
Last post
Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
I've been making progress --

I've been making progress -- just not posting it, so here is a series of updates.

The earlier post of the aligner was the aluminum version.  Here is the PCB version, with Gateron switches installed.

 

 

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
When you have dozens of

When you have dozens of diodes to bend and stuff, what do you do?

Well, you print a bending form.

The divots are appropriately sized for the diods and the width is correct for the PCB holes.  Allows me to bend 10 at a time.

The form is two parts that are identical.  Once the diodes are in place, the top part is put in place to sandwich the diodes in place.

The result is a strip of diodes with nicely bent leads, ready to be clipped and stuffed.

After a bunch of bending, stuffing, and soldering, the board is ready to mate with keys.

 

 

Can you spot the mistake?

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
Time to tackle the controller

Time to tackle the controller board.  Not my best soldering job ever, but its sufficient.  For those wondering, it took two tries.  First one I tried with my hot air gun.  I have an tip appropriate for the package.  Would probably have done well if I had ordered a stencil for the board.  Too hard to get even solder paste spread across the pads from a syringe.  Ended up pulling it off, cleaning it up and doing it a second time with a regular iron and the "drag method".  Came out decent.  Ended up with only one pin that I had to go back and touch up because it wasn't connected.

With that, I added the crystal and its caps, the bypass caps, and programming headers so I could program the chip.  That turned into an escapade in its own right.  Note that the fuse values in the CMakefile comments DO NOT agree with the actual values set by the CMakefile.  Ended up using a Bus Pirate to program the chip.

With the chip programmed and verification that it was at least scanning the key matrix, I put everything else needed, for an Apple II keyboard, on the board.

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
With the controller complete,

With the controller complete, it's time for testing. 

I actually found the badly soldered pin during testing.  Data bit #1 was stuck low.  Tracing it back was when I found the not connected pin.  With that fixed, all data lines toggled and all keys responded as expected.

Now, for the real test!

 

It's alive and appears to be fully functional. 

Oh yeah, did you find the mistake I made earlier?  It's a painful one.  I forgot to install the space bar stabilizer before I mated the keys+aligner to the PCB.  Unfortunately, there will be a bunch of de-soldering in my future to get them installed.

Offline
Last seen: 4 hours 57 min ago
Joined: Apr 1 2020 - 16:46
Posts: 936
Solder paste application ...

In post #54, 'wpmcamara' wrote:

 

"Too hard to get even solder paste spread across the pads from a syringe. "

 

Uncle Bernie comments:

 

the ladies who do the SMD soldering by hand in the company I worked for before retirement used a small brush (and a loupe) to apply solder paste to the solder side of the pins, while holding the SMD with a "suction cup" type tool. Then they positioned the SMD on the PCB, hand soldered and adjusted two diagonal pins, and the rest was done by a  combination of pre-heat and hot air. This technique even works with BGAs. The trick is to get the right amount of solder paste on each pin. I tried to replicate their technique myself but failed. It's not easy. But these ladies had the skill.

 

- Uncle Bernie

Offline
Last seen: 23 hours 25 min ago
Joined: May 31 2022 - 18:18
Posts: 302
UncleBernie wrote: the ladies
UncleBernie wrote:

 

the ladies who do the SMD soldering by hand in the company I worked for before retirement used a small brush (and a loupe) to apply solder paste to the solder side of the pins, while holding the SMD w

 

That sounds like a neat trick, thanks for sharing! I've got some test boards I'm gonna try this on!

Online
Last seen: 1 hour 49 min ago
Joined: Feb 27 2021 - 18:59
Posts: 551
automate

The brush method certainly sounds very difficult.

What works for many is to automate the paste application as much as possible. The goal is to apply the same size dot to all 88 pads (e.g.) of a QFP: so use a device+technique that can repeat the same size dot 88 times. Now the only manual aspect is positioning the syringe and activating the pump.

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
Got back from vacation and

Got back from vacation and decided to tackle my mistake and get the spacebar stabilizer installed.

Made me an 8u stabilizer bar.  Since someone will ask, I have a DU-BRO E/Z Bender Wire Forming Tool.  Makes forming the bar much easier.

 

Installed.

All put back together.  Added a warm white power LED as well.

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
Met up with @dnfr2 this

Met up with @dnfr2 this weekend to get a set of key caps and got them installed.

 

Mounting it was another story.  My Apple II+ has a rev 2 keyboard and mounting the replacement requires removing the controller board to be able to get to the screws.  And the screws are at an angle.  And, when directly mounted, the top lit bumps into the top of the keyboard and can't slide into place.  Still, I got it temporarily mounted and am quite happy.

 

 

 

 

 

I've got some longer 6-32 screws arriving tomorrow and I'll 3d print a space to allow enough room for the lid to slide into place.  Otherwise, its getting close to being called "complete".

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
I printed a set of spacers

I printed a set of spacers and palte to better mount the keyboard.

Both sides have a backing plate to better spread the force of the screws, and accounts for the angle of the screws.

 

Each side also has a spacer.  On one side, it's just a solid block.

On the other side, its a bit more complex because the aligner plate comes all the way over and has cutouts for the screws.

 

With the backing plates and the spacers, I can properly tighten the screws down, without bending or damaging the PCB.  The case lid now clears the aligner board.

 

With that, I'm considering this build done, at least as far as my Apple II is concerned.

Online
Last seen: 1 hour 44 min ago
Joined: Nov 19 2023 - 15:28
Posts: 102
Wahoo very impressive,i need

Wahoo very impressive,

i need a set of keycaps for apple II+ do you know where I can find them ? vincebt

Offline
Last seen: 1 week 4 days ago
Joined: Apr 26 2024 - 18:02
Posts: 15
VIBR wrote:Wahoo very
VIBR wrote:

Wahoo very impressive,

i need a set of keycaps for apple II+ do you know where I can find them ? vincebt

 

If you are looking for originals, then good luck.  Single keycaps show up on Ebay, as well as complete keyboards, but they aren't cheap.  The ones dnfr has will only fit Cherry MX style switches.

Pages

Log in or register to post comments