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Apple iie keyboard issue

DontFryTomato

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Joined
Feb 8, 2023
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15
Hello everybody,

I have an apple iie that I am very slowly restoring. I just discovered that the keys A and Z do not work (meaning nothing is printed when you press them). The rest of the keys are fine. Furthermore, there is continuity for all the keys when pressed, including the A and Z. This should rule out mechanical problems. What should I suspect next? The keyboard ribbon cable?

Thank you.
 

oldpcguy

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Sep 23, 2021
Messages
359
Can you expand upon what you mean by there is continuity? What did you test and how did you test it? For example, did you use a meter to test the two pins of each key?
 

DontFryTomato

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Feb 8, 2023
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Sorry for being unclear. I took the keyboard off and for each key tested the two pins for resistance using a meter. For all the keys the resistance was infinite when not pressed and close to 0 when pressed. This included the A and Z keys that do not work when the system is on.
 

oldpcguy

Experienced Member
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Sep 23, 2021
Messages
359
From the keyboard matrix the A, Z, TAB, and ESC keys all share a common connection (pin one). I would recommend first checking the TAB and ESC keys to see if they're working. If not then test continuity between the following ribbon connector pins:

A - 1 and 16, this connects Y0 to X2
Z - 1 and 20, this connects Y0 to X3
TAB - 1 and 18, this connected Y0 to X1
ESC - 1 and 14, this connects Y0 to X0

Alternatively if testing the keyboard connector pins is difficult you can test the following pins of E14 (the AY-3600 keyboard encoder):

A - 17 and 38, this connects Y0 to X2
Z - 17 and 37, this connects Y0 to X3
TAB - 17 and 39, this connected Y0 to X1
ESC - 17 and 40, this connects Y0 to X0

When the key is pressed you should have continuity and when it is not then you should not have continuity. Testing on the pins of E14 is likely easier than the ribbon cable but it doesn't eliminate the ribbon cable as the problem. To rule out the ribbon cable you need to test the ribbon cable connector pins at the keyboard end (or just check continuity at both ends of the ribbon cable on pins 1 to 1, 14 to 14, 16 to 16, 18 to 18, and 20 to 20).
 
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DontFryTomato

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Feb 8, 2023
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I bet connection 1 is blue, correct? I think I need a new ribbon cable (please see the image). Are they standard? I do not see any specifically for apple ii on ebay but there are many generic ones. Thanks a lot for the post.IMG_20231210_115915518.jpg
 
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oldpcguy

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Sep 23, 2021
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359
I bet connection 1 is blue, correct? I think I need a new ribbon cable (please see the image). Are they standard? I do not see any specifically for apple ii on ebay but there are many generic ones. Thanks a lot for the post.
Yes, typically pin one is the color coded wire. Given this can I assume the TAB and ESC keys also do not work.

As for a replacement I believe it's a basic 26 pin ribbon cable. However I don't know how common they are. You can source a direct replacement from:

Apple Rescue of Denver

Tammy should be able to help you.

NOTE: In the interest of disclosure I occasionally do work for Tammy (picked up five Apple IIe motherboards yesterday). I have no financial incentive to recommend her store.
 

VERAULT

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I bet connection 1 is blue, correct? I think I need a new ribbon cable (please see the image). Are they standard? I do not see any specifically for apple ii on ebay but there are many generic ones. Thanks a lot for the post.View attachment 1269513
New ribbon cable? Are you serious? That could not be an easier fix. Why would you replace the whole ribbon cable?! (n):ROFLMAO:
kirk-slap.gif


In all seriousness I would be happy to walk you through fixing your one single, solitary, easy to fix wire. IF you say you want the ribbon to look nice even though its hidden away from sight I will send Shatner to find you,, and you dont want that.
 
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DontFryTomato

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In all seriousness, I am curious to know how to do it. Still, I don't think I will reuse this one because the insulation is also damaged on the opposite side, with bare wires visible. There were mouse droppings in the case...
And so, I ordered a brand new 26-pin ribbon cable.
 

VERAULT

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In all seriousness, I am curious to know how to do it. Still, I don't think I will reuse this one because the insulation is also damaged on the opposite side, with bare wires visible. There were mouse droppings in the case...
And so, I ordered a brand new 26-pin ribbon cable.
.thats stupid. cancel your order.

if you have a cavity in a tooth should you get your jaw replaced?

strip a little off each end. slip on a half inch of heat shrink tubing
solder wires together. then cover with heatshrink tubing and heat.

Im not sorry to say this.. replacing the entire cable is what an idiot would do.

replacing the cable is like replacing the transmission on your car because your tire is flat.. are you an apple ii owner or a mac user?
 
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VERAULT

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In all seriousness, I am curious to know how to do it. Still, I don't think I will reuse this one because the insulation is also damaged on the opposite side, with bare wires visible. There were mouse droppings in the case...
And so, I ordered a brand new 26-pin ribbon cable.
its one wire.. this is by far the dumbest thing i have seen in a while.. you know what. why stop there. your apple ii is mangled

Replace it with another good one.. i got one to sell you. I also own the brooklyn bridge.. interested in buying.it?

let me guess. you got this advice from the morons on the apple fritter forums? Aka the chruch of steve jobs....
 

oldpcguy

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In all seriousness, I am curious to know how to do it. Still, I don't think I will reuse this one because the insulation is also damaged on the opposite side, with bare wires visible. There were mouse droppings in the case...
And so, I ordered a brand new 26-pin ribbon cable.
I'm not sure what you mean by "I am curious to know how to do it". Could you clarify as maybe I can help.

The cable, at least from the picture, looks as if it had been sliced, perhaps by pulling it against a sharp metal object.
 

VERAULT

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Your right. I came off harsh and I apologize for that.

However I still think buying a new cable to replace one broken wire is just dumb. IT couldnt be an easier fix and if one wire repairs are too much for you that you need to shotgun repair it, than maybe vintage computing isn't for you. Again, this repair is on par with replacing a missing rubber foot as far as difficulty is concerned. You buying a replacement ribbon cable takes it out of the hand of someone who REALLY NEEDS one because its missing or was torn in half (Seen that plenty of times when the keyboard is literally torn from the system). Wasting resources like spare parts is foolish. That was the point I was trying to make.
 
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DontFryTomato

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Feb 8, 2023
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Your right. I came off harsh and I apologize for that.

However I still think buying a new cable to replace one broken wire is just dumb. IT couldnt be an easier fix and if one wire repairs are too much for you that you need to shotgun repair it, than maybe vintage computing isn't for you. Again, this repair is on par with replacing a missing rubber foot as far as difficulty is concerned. You buying a replacement ribbon cable takes it out of the hand of someone who REALLY NEEDS one because its missing or was torn in half (Seen that plenty of times when the keyboard is literally torn from the system). Wasting resources like spare parts is foolish. That was the point I was trying to make.
Thank you again for your valuable opinion. I will think long and hard about whether I should continue.

Speaking of rubber feet, what is the best way of affixing one that has fallen off? It keeps falling off (again and again). Unless properly and timely instructed, I confess I will start buying glue, new and used rubber feet and who knows what else. Thank you!
 

VERAULT

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Oh, OK. I didn't see it as he's on my ignore list.
Why are you ignoring me? Have we ever even talked before in the short time you have been on this forum? Oh wait, you got defensive when I said Steve Jobs wasnt demi-god and pretty much was a lousy person. I still stand by that comment @oldpcguy
 
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DontFryTomato

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Joined
Feb 8, 2023
Messages
15
Yes, typically pin one is the color coded wire. Given this can I assume the TAB and ESC keys also do not work.

As for a replacement I believe it's a basic 26 pin ribbon cable. However I don't know how common they are. You can source a direct replacement from:

Apple Rescue of Denver

Tammy should be able to help you.

NOTE: In the interest of disclosure I occasionally do work for Tammy (picked up five Apple IIe motherboards yesterday). I have no financial incentive to recommend her store.
Thank you for your advice. Replacing the cable solved the problem
 
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