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Speedy

AEK typing gibberish in text entry

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I don't know if this exactly goes into peripherals since I'm not 100% sure the AEK is the cause of the problem here but I dunno where else to put it. I finally got my LC II up and running with the aide of a SCSI2SD, and it's working great! Except for text entry fields. Everytime I type something on the keyboard, I just get gibberish. The weird thing is that the keys themselves seem to recognize okay; I booted up Wolfenstein 3D and I was able to rebind the controls just fine (except for the CRTL key, neither of those will recognize?). Number keys & the numpad numbers work fine as well. I've tried this in a few programs and they all exhibit the same issue. Any advice?

 

Here's a video of the problem:

https://youtu.be/gfBkNOb1954

 

I have it taken apart since I was cleaning it; it was stored poorly by the previous owner and was really dirty on the inside. The very outer sides of the circuit board look like they got corroded by something but all of the traces and solder joints are fine.

Edited by Speedy

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I could be totally wrong because I'm not near a machine right now but I would make sure that one of the control keys (or one of the Apple keys, can't remember which one would cause just the boxes) are not stuck in an applied position. That would make sense for what is being typed when you press the other keys.  I also want to say if you had the keycaps control panel it would show you if a key is being pressed.

Edited by jhorvath911

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I just took a look at KeyCaps and you're right, it looks like both of the control keys are being held down. Hm...

 

 

EDIT: I just tried to reflow the solder on the control keys. No dice.

Edited by Speedy

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Welp, I messed with it again and managed to fix the issue for a split second, but upon pressing CRTL again it reappeared. I have no idea why it could be activating, I even have the switch completely taken apart. I'll poke around more tomorrow.

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Just took apart the other Control key cap, no luck with that either. I don't know what part on the keyboard is causing an issue, if it even a part on the keyboard. I might pick up a PowerMac G3 Biege soon that comes with an AppleDesign Keyboard, so if I get that then I'll try it with my LC II too see if it's a problem with the PC or the keyboard, but I'm really at a loss here. :sad:

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I was thinking it could be the key switch, but if it shows that both the Control keys are pressed, then It's probably shorting somewhere.  You can try following the traces on the PCB for the control keys and see where they end up.  Then see if maybe there's something shorting it, maybe dust or hair, or who knows what.

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I just poked around again and I can't find anything that could be wrong. Just for curiosities sake, I tried booting the LC II with only the mouse connected and going into KeyCaps, and neither Control key showed up as activated. As soon as I put the AEK in though, they showed up as being pressed down.


Also, I should mention, I don't know if both keys are being pressed down or just one of them. Pressing just one of the modifier keys (Crtl, Command, and Option) makes both of them show up as activated in KeyCaps. I don't think I've ever had this much trouble trying to diagnose something :/

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You could try desoldering a keycap from a good key and put it where the control key is.  Could still be the key switch.

 

I think the AEK uses ALPS key switches which you can find online.  I think it's worth repairing because the AEK is one of the best keyboards out there for the Mac.  Great keyboard in general.

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Yeah, my AEK uses ALPS Orange. Very very nice to type on. I'll try what you suggest later today and see what happens - the good news is that if it is the key switch, it's only $5 on eBay for a replacement switch.

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I couldn't figure out how to take the switches out after desoldering, but I did get both of them desoldered and I took them completely apart and prevented them from making any contact with the logic board. After unplugging and plugging the keyboard back in a few times, the Control key eventually released, but upon pressing a totally different key (shift in my case) they went back to being enabled. I'm really starting to wonder where the issue could possibly lie with this thing.

 

I just sent the guy with the PowerMac G3 an e-mail; hopefully I can pick that up and use it to test my AEK, and use its keyboard (an AppleDesign Keyboard) on my LC II to see if it's a problem with that machine.

Edited by Speedy

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Got the G3. Very cool machine, but unfortunately I've figured out that the AEK is at fault. When I initially plugged the keyboard into my G3 though it didn't instantly turn the Control keys on, it only happened after pressing Scroll Lock. I'm going to see if I can figure out what conditions the Control key turns on under.

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I can see a TON of corrosion on that board where something has gotten into the keyboard. you can see the trace rot around the parameter of the board. 

 

I would start there. its probably trace leakage from corrosion or the controller IC itself. 

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I hadn't really put much thought into the corrosion because I didn't see any obvious corroded or damaged traces, just damage to the very outside of the board. If I need to repair traces, what would you say is the best way to go about that? It's a bit out of my area of expertise since I've never had to do that before.

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I thought that maybe something was wrong with the microcontroller, so I started poking around it with my multimeter to see if the pin out for its NEC 80C49 (AEK1 controller) and the Toshiba 80C49 (AEK2 controller) were the same so I could do a replacement, and... the problem went away. I think I checked Pin 20 and 40 (Ground and 5V respectively), and then pin 27, and the problem just disappeared. I tried pressing every key and none of them stuck anymore, although I think left control might be dead. I rarely use that key on Macs however, and even if I built a Teensy ADB > USB adapter so I could use it on my main Windows 7 rig, I could probably live without the left CRTL key. So... problem solved I guess.

Edited by Speedy
grammar + clarification

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Well, I tried to use it again today and it's holding the CRTL key again, but this time it's weirder.  After about 5 seconds of it being plugged in, the key will start to jitter on and off and eventually settle on being on. Now, if you ground Pin 24 (P23, I/O Port 2) the problem will be fixed for an indeterminate amount of time, but it eventually comes back. I'm starting to think the microcontroller is really the culprit here, but I don't have any easy way of replacing it. I think for now I'm just gonna shelve the keyboard until I can buy a replacement chip from Toshiba.

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7 hours ago, olePigeon said:

Could you run a patch wire and permanently ground Pin 24?  Or would that mess it up somehow?

I tried that by attaching a patch wire between Pin 24 and the ground pin, and the CRTL was stuck on while the wire was on. Desoldered it from ground, and the CRTL key wasn't stuck anymore... only for it to go back a few seconds later. It seems like it's totally random if it works for a moment or not.

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