C64 mini keyboard kit – keycap butchery success!

Have been promising a long time to do this, so finally took a few hours to butcher another mini!

Some views are excellent
Another great view
And the worst view

As you can see, for the most part, it’s pretty good, but NOT perfect

what I’ve discovered…..

2 part epoxy works best

Each keycap row is a different depth – the top one needs the least glue, row 3 the most

My errors here. I used a hard plastic glue from Bostick. it doesn’t grip well enough on the top of the keyswitches. I glued everything, waited a few hours, half the keycaps didn’t stick

glued the rest, waited, half again didnt’ stick…rinse and repeat about 6 times, adding more glue till finally they all stuck.

The 2 part epoxy stuck fast and hard! – but I used too much.

The repeated adding of more glue caused the multiple key levels you can see in the picture

I’ll try one more time I think!

Amusing story and reversed switches on the C64 mini keyboard kits

Correct orientation of the switches
Correct orientation from the top. (Except the shift lock…oops! That’s why I put extra switches in :-p)

A funny story about multi sourcing components and the importance of testing before shipping!

I used a supplier on Aliexpress to purchase a few thousand switches in a few orders over a few months but their prices went up quite drastically after the last order (doubled!!) they weren’t the cheapest to start with but were reliable and friendly, worth the extra ££

I found another supplier who did a good deal for a full bag of 4000! Ordered them and waited, very quick delivery and friendly also (will buy again!)

I built my first test new keyboard with the new PCB and switches

It didn’t work. Well, actually, it did! Work perfectly…but in reverse :-p …..

If you mashed every key simultaneously then only released the key you want to press….it worked!! Yeah, the supplier sent me 4000 ‘inverted’ switches! My fault for not checking prior to ordering, they ‘look the same’ so ‘must be the same’ was a wrong assumption on my part! (At least they all weren’t the shift lock type!!)

It’s a VERY easy fix though (found after several panicked hours of testing and building Keyboards)…rotate the switch 180 degrees and it’s perfect!

In each kit I’ve included a small errata note and list of basic instructions to help. It’s an annoyance but for you guys it really just means the silk screen doesn’t quite match the switch orientation so just ask first. Look at the pictures and of any doubt, email/messenger/twitter/Reddit me 🙂

Assembly of the C64 Mini working keyboard kit! – PICTURES

Follows a couple of pictures of the install, I’ve also put a couple of videos up on youtube. More will follow

DIODE orientation. Note, make sure they’re all the same way round. One here isn’t!

I’ve put some videos up on youtube about the assembly process – the playlist is linked below

Putting the switches in Wonky for the first round of alignment (smt diodes hand soldered on the original prototype)

Make sure you solder the arduino headers on before you get this far with the switches

Back of board showing Diode legs clipped and only ONE switch pin tacked per switch

USB HUB TO FOLLOW – Pictures shown in blog previously if you need them quickly

Assembly of the C64 Mini working keyboard kit! – TEXT

Some quick steps right now – photos to follow.. Suggest have two tabs open, this one and the other PICTURES tab for reference

Some videos are up on youtube also

Link to Youtube videos

SUMMARY- SOLDER PARTS ONLY IN THIS ORDER

DIODES

ARDUINO HEADERS

SWITCHES

DIODES

  • Cut one leg shorter on the diodes – Use scissors . About 1-1.5cm is good
  • bend the short leg side to a right angle
    • Note the orientation of the diode – The F Key diodes have a diode picture on them. The white bar matches the location of the black bar on the diode.
  • put diode in holes and bend slightly to lock in
  • repeat for all diodes
  • Solder all diodes
  • clip the excess legs back
  • you have a few spare diodes so don’t be afraid to experiment on one or two to get the right bend / fit

ARDUINO HEADERS

  • Probably best to solder these in now before you forget
  • I’ve found it useful to PLACE the arduino on the headers (DO NOT SOLDER YET) so it keeps the headers parallel
  • Make sure the black part of the headers is on the underside of the PCB
  • Solder one pin of each header
  • remove arduino
  • finish soldering

SWITCHES – STEP 1, JUST TACKING IN PLACE

  • Pay attention to orientation
  • don’t worry about straightening the switches at this stage, the goal is to just ‘tack’ them in with a single solder blob to hold them in place. They can be wonky, it doesn’t matter.
  • DO NOT SOLDER MORE THAN 1 PIN OF EACH SWITCH IN ONE GO
    • The switches are easily heat damaged – they become ‘sticky’ and no longer move smoothly if the plastic is melted due to excessive heat. During the entire soldering procedure for the switches, do ONE leg, move to the next switch. when all are done, move back to the first switch and repeat.
    • I’ve damaged only 2 switches this way soldering the prototypes but it can happen if you’re not careful
    • Note that the white part of each switch is asymetrical. One side has a ‘dip’ / inset which guides the switch up and down. the other side is smooth
    • there’s a marking on the PCB to represent this dip / inset.
    • ALL switches go the same way
  • Get a sheet of paper
  • Insert the top row of switches into the PCB
  • Place PCB on sheet of paper and fold paper over the top, tightly
  • flip the PCB over
  • hopefully all the switches stay in place
  • Solder just ONE leg of each switch – any one – say the top right
  • Repeat for Row 2
  • DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
  • Repeat for Row 3
  • DO NOT FORGET TO SOLDER THE ARDUINO HEADERS IN PLACE
  • Repeat for for row 4
  • (Hopefully you didn’t forget to solder the Arduino headers in place?)
  • and finally the space bar

SWITCHES – STEP 2, Straightening

  • This is probably the most important step to getting a good looking keyboard with all the switches aligned. Spend some time getting this right, you have a handful of ‘spare’ switches so now’s the time to make mistakes and fix them whilst there’s only a single solder blob on them
  • I’ll post a few videos shortly but there’s a technique.
  • Hold the board in the air
  • Use your index finger to push in, and slightly down on each switch whilst soldering the previous blob. The goal is to move the whole switch slightly so that it’s slightly at the top, or the bottom of its footprint.
  • when you melt the solder whilst pushing in and down, the switch will move slightly, sometimes you’ll hear a little click or snap as the solder melts
  • repeat this for each switch, pushing in and down slightly – when you look at the final position, there’ll be some of the pad visible at the top of each switch
  • NOW IS THE TIME TO TEST EACH SWITCH FOR SMOOTH MOVEMENT
    • of the 5 keyboards i’ve soldered, I’ve had two defective switches, this is partly the reason why there’s a few extras in the kit
    • of the 5 keyboards i’ve soldered, I’ve broken 3 switches by either over-heating, or trying to remove after putting them in backwards. unless you’ve got a hot air gun, they’re tricky to remove intact, hence check NOW whilst there’s only one solder blob!
  • When you get close to one side of the keyboard, you’ll have to fiddle a bit to keep pushing the switches in the same direction. I’ve found that changing technique a little and ‘flip’ the board lengthwise works. hold the board against yourself and use your thumb to pull the switch down instead of push
  • repeat the alignment technique for ALL switches!

SWITCHES – STEP 3, Final soldering

  • This is the easy / relaxing bit!
  • DO NOT SOLDER MORE THAN ONE LEG OF EACH SWITCH AT A TIME
  • do it by rows, clusters, however works for you, but here’s what worked for me
  • Solder ONE pad of each switch, then move to the next
  • once all switches are done, start from the beginning
  • Solder another pad, etc etc
    • A SMALL CHEAT – You only actually need to solder 3 points. Two on the ‘bottom’ of the switch – these are the electrical contacts. ONE on the ‘top’ – this is for mechanical stability. As you look at the keyboard, the bottom two pins are the important electrical ones. Pick any on the top
  • on my prototype, I found soldering all 6 pins tiring, so on my second version I just soldered 3 and it worked perfect. Up to you, but DONT SOLDER MORE THAN 1 PIN AT A TIME

Arduino

  • Note the orientation of the Arduino by the Small USB socket and a mark on the PCB. Also the silk screen on the PCB will match the letters on the Arduino.
  • these need a little more heat to solder to the pins

Finished Keyboard!!

The Hub

C64Mini working keyboard – The Butchery Part 1

Time’s progressing and it’s still taking a long time to obtain a satisfactory print of my CAD keycaps. Some quotes have come in and…they’re quite a bit.

so, time to change focus for the short term to let me actually play games on the mini with all the keyboardy goodness that a working keyboard will allow

So, on to some butchering

The Plan….create a plaster of paris negative of the original keyboard – to hold the keys straight when attaching them.

Step 1 – Print out the case design from my last post

Fits like a glove……..or does it?

Step 2 – realise that I’m making a NEGATIVE and the keyboard needs to sit INSIDE the box, ‘upside down’ Redesign and re-print…

Better

Step 3 – Coat liberally in spray oil… Wife wasn’t too happy that I’d used her pricey artisnal olive oil from our trip to Italy, nothing but the best for my Mini though………

Step 4 – Knock up a batch of pancake batter Plaster of paris…About 50 grams of powder and 60ml water worked for mine….not too viscous.

fill the keyboard case just over 1/2 way to measure what you need

Step 5 – Fill up the mould

Screw on the keyboard – making sure the keys are aligned and straight with the F Keys and wait overnight…

Use the holes either side to top up the plaster so it overflows a little

Give the whole combo a dozen or so short sharp drops / knocks on the table to free up any air bubbles

Mmmmmmm….Keyboard Cake?