TweetFollow Us on Twitter

Keyboard repair
Volume Number:5
Issue Number:1
Column Tag:The Electrical Mac

Keyboard Repair

By Richard Clark, Mission Viejo, CA

The Incredible Dying Keyboard

I have a confession to make - I don’t own a Mac Plus. What I do have is an ancient 512Ke which began life as an early 128K. It’s had two power supplies (“analog boards” to those in the repair business), two keyboard cables, a new 512K mother board, and an Incredible Dying Keyboard. A different key dies about once a month now; there’s no warning, the key just stops working.

The Incredibly Frustrating Repairman

Fixing a broken key is supposed to be simple for the repairman - you just open up the keyboard, remove the old switch, and solder in a new one. It’s a five minute job, and that includes waiting for the soldering iron to warm up. There’s only one problem: “the rest of us” can’t get the special keyboard switches that Apple uses. After a run-in with one particular dealer who refused both to sell individual switches and to fix the keyboard (he wanted to sell a new keyboard for $130), I decided to open up the keyboard and see what I could do.

Fixing Dead Keyboards is Easy (and cheap)

I learned that, with some limited soldering and mechanical skills, most keyswitch problems can be fixed. You remove the switch, make an adjustment or two, and replace it in the keyboard. It’s easy and works almost all of the time. So far, I’ve managed to repair 11 out of 12 dead switches myself (and the one failure was because I tried a shortcut which damaged the switch beyond repair.)

Notice that these repair techniques only work in the case where the switch is the culprit. Also, I haven’t tried these with one of the new ADB keyboards, but Apple seems to be using the same switch supplier, so this should work. Also, these techniques may not apply to “locking” keyswitches (like the Caps Lock). If the entire keyboard is dead, then I can’t help you (except to say “take a good look at your keyboard cable” because if you stretch the cable too much you can pull the connections apart inside of the clear connectors.) If the whole keyboard is dead, and it isn’t the cable, then you’ll need a new keyboard since Apple doesn’t supply the spare parts for fixing the keyboard electronics to anybody.

Now that we’ve gotten the disclaimers out of the way, we’ll discuss what you’ll need. First, you’ll need some basic soldering equipment: a soldering iron, solder (use only rosin-core solder, not acid-core) , and some sort of solder remover. The vacuum-type removers seem to work better than “solder wick” for keyboard work. A small can of flux remover (sold in Radio Shack as “cleaner/degreaser”) is optional but helps tidy up the keyboard after you’re done.

You’ll also need some basic tools and supplies: a medium-sized Phillips screwdriver (about 1/4”), two or three small straight-blade screwdrivers (about 1/8” across), a pair of needle-nose pliers, and a pair of scissors or an X-Acto knife. You’ll need two small pieces (about 3“ each) of wire, stripped at both ends. And, depending on the problem you’re fixing, you’ll need either a small tube of cement or some self-adhesive labels.

Finally, you’ll need to know how to solder and unsolder on single-sided printed circuit boards. Anybody who’s built a Heathkit or two will understand how to do this. If you’ve never handled a soldering iron before, then get a friend to help.

The Secret Life of Keyswitches

OK, if you’ve gotten this far, then you’re interested in fixing keyboards. So let’s talk about how keyboards work. Looking at Figure 1, you can see that a keyswitch consists of five major parts: the upper and lower case sections, the stem, a spring, and a “contact assembly”. The contact assembly consists of a plastic frame containing two metal pieces shaped in such a way that when you press on the front of the assembly, the metal pieces come together and close the switch. When you press down on a key, the stem travels downward, resisted by the spring, and presses on a small metal tab sticking out of the front of the contact assembly. This compresses the assembly and closes the switch. When you remove your finger, the spring pushes the stem back up which removes the pressure from the contacts and opens the circuit again. The keyswitches are wired to an “encoder” which turns the switch closure into a signal for the Mac.

So, how does a keyboard break? Well, there’s 2 common problems: if the switch just quits working (or works only if you press the key hard and/or wiggle it around), then the contact assembly is wearing out. Or, if the key seems to be “floating” - that is, the keycap is a little higher than all of the others and is putting out multiple characters on each press - then the upper and lower case assemblies have come apart and aren’t guiding the stem properly. Both of these problems are easily fixed.

Fixing Keyboards: Step by Step

So, here’s the step-by-step procedure for repairing a Mac keyboard:

1. Organize your tools and plug in the soldering iron. Detach any cables connected to the keyboard.

2. While the soldering iron is warming up, turn the keyboard over and remove the 5 phillips-head screws holding the bottom of the keyboard case on. Remove the bottom casing and set it aside, then lift out the keyboard assembly. Set the top casing aside with the bottom casing.

3. Using a flat-blade screwdriver, pry up the key cap from the broken key and any surrounding key caps that might get in your way.

4. Turning the keyboard over, locate the 2 pins coming out of the broken switch. (I typically circle them with a pencil after I find them, just so I don’t have to search for them several times.) Unsolder these connections, being careful not to overheat the connection and lift the foil up off of the board.

5. Using a pair of needle-nose pliers, gently move the unsoldered pins to be certain that they are completely free from the sides of the hole.

6. Turn the keyboard back over, so that the key caps are on top. Referring to Figure 2, press in on the 2 tabs at the top and the bottom of the switch. While you are pressing these tabs inwards, lift out the switch. Please resist the temptation to use pliers on the stem of the switch - you could break or damage the stem beyond repair. Having a second person comes in handy here!

7. Now that you have the switch out, you can begin the repair. If the problem is a “floating” keyswitch, then just glue the top and bottom halves of the switch together (making sure that all of the pieces are inside, of course), and skip the next step. If the problem is the more common “dead switch” type, then do the following:

a. Using a pair of small screwdrivers (X-Acto #2 knife blades also work well), and looking at Figure 3, insert the blade of the screwdrivers between the gray tabs and the black upper body. Press the blade all the way down to the bottom of the case on both sides and the two halves will pop apart. Pull the case halves apart, being careful not to lose the small spring.

b. Stack 2 or three layers of self-adhesive paper labels together (I use a spare disk label), and cut it to about 3/8” square - a little smaller than the back of the contact assembly. Then, referring to figure 4, stick this paper “shim” to the back of the contact assembly. When a keyswitch dies, it’s usually because the contact assembly has nothing to press on behind it. The labels provide the necessary backing.

c. Carefully re-assemble the switch. Because of the labels, it may take a little pressure to get the top and bottom casings back together. Don’t forget to install the spring!

8. Now it’s time to test your work. Using the 2 pieces of wire, solder one end of each to each of the pins on the back of the switch. Solder the end of one wire to one of the pads on the keyboard where the switch was soldered, and solder the other wire to the other pad. Now plug in your keyboard, turn on your Macintosh, and test out a few keys, including the one you just modified. If the modified key fails, then take it apart and check your work. Re-assemble it again and try again.

9. Unsolder the wires from the keyboard and keyswitches. Then check that the pins are sticking straight out from the back of the switch and straighten them if necessary. Next, put the switch back into the hole in the keyboard where you removed it. Make sure that the pins in the switch enter the holes in the circuit board, and press the key in until the gray tabs snap into place.

10. Re-solder the switch into place and (optionally) spray a little flux remover on the connection just to clean things up. If you use cleaner, be careful not to get any inside the switch!

11. Re-assemble the keyboard, and you’re done!

The whole process should only take about a half hour the first time you do it, and about 10 minutes each time after. As I noted before, I have 11 keys on my keyboard modified this way (fixed with a stack of paper labels), and the earliest repairs have been working perfectly for a year now.

Unlike most MacTutor articles, you won’t be getting a program listing with this one! So I hope that knowing how to fix your own keyboards will satisfy both you and David Smith. Happy Hacking!

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Six fantastic ways to spend National Vid...
As if anyone needed an excuse to play games today, I am about to give you one: it is National Video Games Day. A day for us to play games, like we no doubt do every day. Let’s not look a gift horse in the mouth. Instead, feast your eyes on this... | Read more »
Old School RuneScape players turn out in...
The sheer leap in technological advancements in our lifetime has been mind-blowing. We went from Commodore 64s to VR glasses in what feels like a heartbeat, but more importantly, the internet. It can be a dark mess, but it also brought hundreds of... | Read more »
Today's Best Mobile Game Discounts...
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links below... | Read more »
Nintendo and The Pokémon Company's...
Unless you have been living under a rock, you know that Nintendo has been locked in an epic battle with Pocketpair, creator of the obvious Pokémon rip-off Palworld. Nintendo often resorts to legal retaliation at the drop of a hat, but it seems this... | Read more »
Apple exclusive mobile games don’t make...
If you are a gamer on phones, no doubt you have been as distressed as I am on one huge sticking point: exclusivity. For years, Xbox and PlayStation have done battle, and before this was the Sega Genesis and the Nintendo NES. On console, it makes... | Read more »
Regionally exclusive events make no sens...
Last week, over on our sister site AppSpy, I babbled excitedly about the Pokémon GO Safari Days event. You can get nine Eevees with an explorer hat per day. Or, can you? Specifically, you, reader. Do you have the time or funds to possibly fly for... | Read more »
As Jon Bellamy defends his choice to can...
Back in March, Jagex announced the appointment of a new CEO, Jon Bellamy. Mr Bellamy then decided to almost immediately paint a huge target on his back by cancelling the Runescapes Pride event. This led to widespread condemnation about his perceived... | Read more »
Marvel Contest of Champions adds two mor...
When I saw the latest two Marvel Contest of Champions characters, I scoffed. Mr Knight and Silver Samurai, thought I, they are running out of good choices. Then I realised no, I was being far too cynical. This is one of the things that games do best... | Read more »
Grass is green, and water is wet: Pokémo...
It must be a day that ends in Y, because Pokémon Trading Card Game Pocket has kicked off its Zoroark Drop Event. Here you can get a promo version of another card, and look forward to the next Wonder Pick Event and the next Mass Outbreak that will be... | Read more »
Enter the Gungeon review
It took me a minute to get around to reviewing this game for a couple of very good reasons. The first is that Enter the Gungeon's style of roguelike bullet-hell action is teetering on the edge of being straight-up malicious, which made getting... | Read more »

Price Scanner via MacPrices.net

Take $150 off every Apple 11-inch M3 iPad Air
Amazon is offering a $150 discount on 11-inch M3 WiFi iPad Airs right now. Shipping is free: – 11″ 128GB M3 WiFi iPad Air: $449, $150 off – 11″ 256GB M3 WiFi iPad Air: $549, $150 off – 11″ 512GB M3... Read more
Apple iPad minis back on sale for $100 off MS...
Amazon is offering $100 discounts (up to 20% off) on Apple’s newest 2024 WiFi iPad minis, each with free shipping. These are the lowest prices available for new minis among the Apple retailers we... Read more
Apple’s 16-inch M4 Max MacBook Pros are on sa...
Amazon has 16-inch M4 Max MacBook Pros (Silver and Black colors) on sale for up to $410 off Apple’s MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather than a third-party... Read more
Red Pocket Mobile is offering a $150 rebate o...
Red Pocket Mobile has new Apple iPhone 17’s on sale for $150 off MSRP when you switch and open up a new line of service. Red Pocket Mobile is a nationwide MVNO using all the major wireless carrier... Read more
Switch to Verizon, and get any iPhone 16 for...
With yesterday’s introduction of the new iPhone 17 models, Verizon responded by running “on us” promos across much of the iPhone 16 lineup: iPhone 16 and 16 Plus show as $0/mo for 36 months with bill... Read more
Here is a summary of the new features in Appl...
Apple’s September 2025 event introduced major updates across its most popular product lines, focusing on health, performance, and design breakthroughs. The AirPods Pro 3 now feature best-in-class... Read more
Apple’s Smartphone Lineup Could Use A Touch o...
COMMENTARY – Whatever happened to the old adage, “less is more”? Apple’s smartphone lineup. — which is due for its annual refresh either this month or next (possibly at an Apple Event on September 9... Read more
Take $50 off every 11th-generation A16 WiFi i...
Amazon has Apple’s 11th-generation A16 WiFi iPads in stock on sale for $50 off MSRP right now. Shipping is free: – 11″ 11th-generation 128GB WiFi iPads: $299 $50 off MSRP – 11″ 11th-generation 256GB... Read more
Sunday Sale: 14-inch M4 MacBook Pros for up t...
Don’t pay full price! Amazon has Apple’s 14-inch M4 MacBook Pros (Silver and Black colors) on sale for up to $220 off MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather... Read more
Mac mini with M4 Pro CPU back on sale for $12...
B&H Photo has Apple’s Mac mini with the M4 Pro CPU back on sale for $1259, $140 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – Mac mini M4 Pro CPU (24GB/512GB): $1259, $... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.