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Neglected PET needing some love

I haven't been able to get the keyboard working to an acceptable level. You can type on it but you're going to be either slamming the keys or constantly going back and correcting characters that either didn't type or typed multiple times.

After a lot of consideration I decided to go ahead and try making the mechanical keyboard. I found it won't be quite as expensive as I thought as there is a cheaper, slower, shipping option on the PCB and the MX switches on amazon did have an option to select 88 switches instead of 68 for only a few dollar more and a $5 coupon if you pick yellow (like I care what color the switch is).

My plan is to try to do it as a direct replacement to the existing PCB (at least as much as possible). This means I will need to design & print some custom key plungers to make use of the existing key caps and possibly some standoffs to move the PCB further away from the black plastic keyboard frame so as to create clearance for the MX switches.
If it works it should be a pretty nice upgrade as it should still have the same look but just be much better working and more serviceable in the future.

I'll post updates after I get the PCB.
 
okay got the keyboard pcb's, soldered on the key switches, all seem to work. I used a ide ribbon cable to connect it to the pet.
but the pcb want designed to be used with the original keyboard frame and the key positions don't quite align so I think I'm going to have to do without that. I'll either need to use all new keycaps or make some kind of adapter to adapt the original keycaps to the mx switches
 
I am not sure if this model of PET has the "graphics" characters normally printed on the front of the keys, but I did an TexElec build of their MiniPET keyboard, and I used blank keycaps and applied these labels to it. Mind you this is for the 20 key pad to the right and not the 12 you have, but it might be doable for you if you can't get the original keycaps on the MX switches.

PET Keycap Labels
 
Anyone here handy with the PCB design software Kicad?

I've read recently that the newest version includes an interesting feature, the ability to import a scan or a photo of an original PCB so that you can 'copy' it by drawing the tracks, through holes and so on of your PCB over the original ones to produce a near perfect 'traced' copy. In this case your design would in the final stages have to deviate from the original to accommodate your replacement switches instead of the original 'contact fingers' pressed on by the rubber pills, assuming the aim is to make a one for one PET keyboard PCB which can take actual switches.
 
I thought I'd post an update on this project. I have the mechanical keyboard working but still some work needs to be done on it.

The positions of the keys aren't 100% the same as the original PET's keyboard PCB so I couldn't use that black plastic frame. Instead I mounted the PCB on a block of wood. I made little 3d-printed inserts that could go into the key caps to attach them to the MX switches but then found out that the shift keys are too wide and I can't re-use the space bar because the cylindrical part of the spacebar's plunger is not a separate (and detachable) piece but is just part of the whole spacebar mold. (mould, sp?)

So I'm waiting on some new key switches. These are what I went with (the 143-blank variant, not labeled, strangely I don't see that variant anymore) but until I get them I don't know how well they'll work.

Now that we have some nice weather I've been working on the case. I sanded off all of the paint & rust from the outside and used black rust converter on the inside. Then I tried to match the paint color to that of the monitor but I was off a bit (it's greener than it should be) but all-in-all I'm happy with it.

Of course all of this is way off base with the original look what with modern keycaps, different paint color, the apple monitor 3, etc... but I've been careful that all of the mods/changes I'm making are reversible and I'm not throwing out any unused parts so if I sell it later in life the new owner could make it original again.

When it's all done I think it will look as if Apple had decided to make a PET clone instead of the Apple 3 :)

Oh and I know some of the keys are twisted, the MX switches were a little out of alignment when I soldered them in so desoldering those and straightening them out is on my to-do list.

pet_painted.png
 
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Alright I'm just about done with this project. I have a working keyboard:
petKeyboard.png
(although some of the keys still need to be straightened)



I picked up a PetDisk and have been toying with it today so I have a way to load software. One thing I'd really like to do with it is some BBSing.
I was hoping I could use the same userport wifi adapter I use on my C64, but I guess the pet's user port is not the same as the c64's? When I plugged it into the pet there was no signs of life on the wifi adapter (it has an LCD screen that would light up otherwise). Maybe there's a pet-specific wifi modem option out there somewhere?
 
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