Dead Apple Keyboard II Repair - where to start ?

[Dj Mike]

Anyone ever repair one of these ? Where to start repairing one. Apple Extended Keyboard II - I already have it apart. It's an ALPS version.
Nothing is broke physically, but there is no response when ANY of the keys are pressed.
I'm relatively new to repair work, so I need a dumbed down version the first time around.

 

[GiGaBiTe]

Start by checking continuity, if the keyboard is not responding at all, I'd suspect something like a broken wire or solder joint.

Beep out the ADB cable and make sure all four wires are good. Also make sure the connectors to the PCB inside the keyboard don't have cracked solder joints.

 

[AndyO]

I had one a few years ago where the tiny surface mount fuse had blown due to it being connected or disconnected while the system was powered up. The symptom was the entire keyboard was dead. Fairly simple repair, and worth checking.

 

[Dj Mike]

I had one a few years ago where the tiny surface mount fuse had blown due to it being connected or disconnected while the system was powered up. The symptom was the entire keyboard was dead. Fairly simple repair, and worth checking.

I had one a few years ago where the tiny surface mount fuse had blown due to it being connected or disconnected while the system was powered up. The symptom was the entire keyboard was dead. Fairly simple repair, and worth checking.

where would the surface mount fuze be located on the PC board of the Apple Extended keyboard II ??? Any one have schematics ???

 

[JDW]

A lot of people overlook the need to recap anything with a fluid-filled electrolytic capacitor on the circuit board, somehow thinking there are exceptions to the golden rule which says "no electrolytic capacitor has eternal life." I know that to be true myself. Some years back, my SE/30 was freezing for reasons unknown. Eventually, I decided to open the IIgs ADB keyboard I was using, and sure enough, it had an electrolytic capacitor. I swapped it out for a solid tantalum, and I've not had a problem since.

Keep in mind that on some keyboards, there are also ICs which can be shorted out by spilled drinks. You'd be surprised how many keyboards have been killed that way, sometimes slowly over time! So you may need to swap a chip in order to get it working.

Then of course, you would need to check traces with a magnifying glass to see if any have been severed. If someone removed the PCB in the past for cleaning after a spilled drink, they might have bent it too much, resulting in a hairline crack that eventually severed an important trace.

Also, check your cables because that could be the culprit. And never connect ADB devices or remove them while your Mac is powered.