M0110 Keyboard not working... help me troubleshoot?

[olePigeon]

I have an M0110 with intermittent keys.  Some of the keys don't work, a handful work just fine.  Some I can press hard and they'll register, others I have to press at an angle.

Could it really be that most of the key switches are bad?  Or could it be something else?  I gave it a good hot bath, but no change.

I suppose I could swap a working keyswitch to the spot of a not-working one.  That would help me determine if it is indeed the switches and not something else.

 

[fri0701]

I'd suggest first testing the intermittent keys with a continuity tester to see if they are the problem, or if the problem lies elsewhere. If they don't work reliably with the tester, there's your problem. If they do, then you may have larger problems...

Do the traces on the back of the board look clean and non-broken? It may be useful to test these with the continuity tester as well, just to make sure.

 

[Elfen]

This is the old keyboard that came with the Mac 128/512/Plus?

Opening it is simple as it is 6 screws I think, and pulls apart with ease. You can wash the plastics while looking at the actual keyboard. They are the same switches used on the IIe and later II+. The IIc uses a smaller version of the same switch.

Check the solder side for broken solder joints. If any are found, desolder, clean the area and solder with fresh solder. Check the solder around the jack and check the traces from switch to switch. that should improve things.

But for bad switches, god... there are a few tricks. Get a lasagna tray and fill it with high proof rubbing alcohol. Dunk the keyboard in it and slosh it about for a while. A long while. It will rinse out the crap inside the switches. Let it dry out and try it out.

If the switches are actually broken, there are replacements. Like I said, IIe and newer II+ keyboards used the same switch. And it is a standard unit. If you can desolder one from the board, the model number is on the bottom of the switch next to the pins.  Just need to track it down. Mouser might have it. Newark might have it. JDR(?) Micro Devices might have it.

 

[unity]

If you just want to replace it, let me know. I still have a few spares I think and can test one out. Not sure about the keyboard itself, I never had a bad one, but I had a broken off key on the keypad accessory. It was hell replacing the switch.

 

[olePigeon]

An update:  I swapped a couple keyswitches, and it's definitely the switches and not the board or ROMs.  A hot bath didn't do anything.  However, I've been able to get most of the keys back by pressing hard and wiggling it.  I'm guessing there's some corrosion in the key switches.  Maybe from humidity?  By pressing and wigging, I'm guessing it's scrapping at the corrosion and making contact.  I'm going to continue doing it, see if I can get all the keys working again.

The manufacturer sure used high quality solder.  Even after all these years, the solder on the switches melted like they were just soldered on.  First time I've ever encountered that.

Just used a pair of tweezers and the switch comes right out.  I found it rather easy.

 

[Elfen]

Taking apart the switch is simple as it is removing it. It is putting it back together that can be a pain in the rear! The slide pushed on a rocking brass piece that makes contact with the tabs the pins are connected too. It is the tab that corrodes if something was poured onto the keyboard. They usually last forever under normal use.

There are two tabs on the side that you press in and the switch pulls part like a space shuttle pulling itself out from dock at the space station - literally! Just take it slow when you do or the spring will fly out and get lost. To taunt you, it might even pop out and hit you in the face before running away!

Another design of the switch, there are tabs a the bottom that need to be pulled out before the switch can come apart.

 

[olePigeon]

What's the best item for cleaning them?  Contact cleaner?

 

[olePigeon]

I was able to get them all to work rather reliably except the right bracket key.  Looks like I'll need to take that one apart.

Also looks like I need to recap the analog board as the screen started to shrink from the top down.

 

[CC_333]

Yes, contact cleaner should do the job. Make sure you get good quality stuff, though.

I *might* have an extra key switch around somewhere, if you need it.

c

 

[techknight]

if you had an electroplating machine, you could take all the contacts out, dip them in TarnX, clean them, and then re-plate them. theyll work after that. 

I had to do this 1 time on a Tormat that went into a seeburg jukebox, but I had to send the metal out to get plated though. 

 

[Compgeke]

A bit of info on the switches: The M0110 uses Alps SKCC "Cream" with an SKCC lock for capslock. A fair bit of M0110As actually use the same switches however the A has a bit of variation in that some have a Mitsumi or SMK-made switch. Easy way to check is the Alps one has a tall off-white stem, Mitsumi are white and SMK are black. 

Here's some pictures of one of the linear SKCC switches being taken apart, could help with fixing non-responsive ones. http://i.imgur.com/W9ib8a4.jpg and http://i.imgur.com/UFB1JAW.jpg  (from: http://imgur.com/a/BUJCJ#d73rvGq )

I'd assume a decent alcohol-based contact cleaner would bring the switches back to life. If anything like audio gear years of dirt\poor storage\moisture causes switches and pots to be very temperamental, fix being a contact cleaner. The usual in the audio world is deoxit however that stuff's expensive, a generic one would work fine for a keyboard switch.

 

[olePigeon]

Took the switch apart, and I didn't see any corrosion what-so-ever.  However, when I put it back together and soldered back in, I couldn't get the key to work. :-/

 

[techknight]

What about the contact points? were they present, and not rounded off and eroded away? 

 

[olePigeon]

I'd have to take the key apart again.  Seems like a really simple switch.  Maybe I can just bend it.

 

[olePigeon]

Hah!  Fixed it!  There were about 8 keys that weren't responding or wouldn't respond without firm pressure.  I just desoldered them, popped them out, opened them up, bent the 2 prongs outward, then reassembled.  It was super easy to do, only took about 30 seconds a key cap once I got it down.

The 8 keys I worked on have a much more satisfying key action, with a better tactile "pop" compared to the other keys.

Works great now.  Time for some Retr0Brite.

 

[CC_333]

Excellent!!

It's probably too much work, but maybe you should adjust all the other keyswitches so the key action matches?

c

 

[techknight]

That keyboard probably had the crap used out of it... Glad its working though