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Apple IIgs Keyboard Issue


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I've recently purchased an Apple IIgs to add to my IIc and am having a keyboard issue. Basically it appears to be complete dead. I can plug the mouse direct into the rear of the IIgs and that seems to work fine as I can get the cursor moving, however, when I plug the mouse into the keyboard, and then the keyboard into the back, nothing seems to work. In my brilliance, I tried an S-video cable as it appeared to have the same connector and that didn't work either. As I'm completely new to this system, I'm not completely sure of any specific keyboard combinations, etc. to try. Heck, I'm no even sure if there an on/off switch I'm missing...


I'm fairly handy with my soldering iron and multimeter and was hazarding cracking it open to see if I can see anything out of the ordinary. Any suggestions to try or something to look for?


Thanks in advance!

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As a bit of a follow-up to this, the keyboard appears to be working using the RIGHT side connector direct to the rear of the computer. When the mouse is connected to the LEFT side, no movement. My next guess, is that the left-side connector has possibly come loose from the keyboard pcb in some way to make that side only non-operative. I unscrewed the keyboard to see what I could see, but it looks like I'll need to pull the keys to get at the pcb. Week-end project, I guess...Thanks!

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Hmm. Shouldn't have to pull any keys if this is the stock IIgs keyboard (no function keys at the top) to get to the PCB. Just verified on the one sitting next to me. There are just 3 screws along the back, then you have full access to the solder side of the PCB.




If it has a row of function keys, then it's probably the Apple Extended keyboard they sold for Macs. It's ADB and will work with the IIgs.


Either way, glad you found the issue. 

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I tested continuity from one side of the keyboard pcb to the other using like numbered pins near each connector with no continuity issues. Doesn't look like a bad solder job either, so I cleaned the solder joints with IPA along with using contact cleaner in the connector itself. No dice. I'm suspecting that the connector itself on the keyboard is bad in some way. I'm looking at this in a lazy-kind of way, but I'm wondering if an s-video cable splitter would work? I can plug it up like this:


1. One end of the keyboard cord into the right side keyboard connector then the other end into the splitter.

2. Mouse directly into the splitter.

3. Splitter into the rear of the computer


Functionally, this looks right. Electrically, I have no clue.

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I'm not sure if just a dumb splitter can be used. You could test the port itself though. You said you had an svideo cable, plug that in to the bad port and check continuity from the end of the cable to the PCB. Alternatively if you have a through hole component with the proper diameter lead laying around, you could just insert that into the socket and test continuity from the leg to the PCB.


If you do find the socket is bad, given that is a standard pinout, you can probably find a suitable replacement at Mouser or Digikey, or whatever electronics parts warehouse. 

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On 11/30/2022 at 11:29 AM, The Usotsuki said:

I'm pretty sure the S-Video cable is exactly the same as the ADB cable.

I think they have a different idea of which pin is ground.


(...quick check of google...)


Yep, S-video has ground on pins 1 and 2, and any random S-video cable could short them together. ADB might have a problem with that. Having the data pin paired with Vcc isn't great either, but there probably won't be enough noise to make a difference.

adb pinout.png

Edited by Bruce Tomlin
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