Does Anyone Have a Spare Apple IIe Platinum Keyboard?

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Wiggle Wiggle's picture
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Does Anyone Have a Spare Apple IIe Platinum Keyboard?

My Apple IIe platinum keyboard just failed on me. Does anyone out there happen to have a spare they'd be willing to sell me at a reasonable price? I'd really like to get back to gaming on my apple.

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Whole keyboard failed? 

Whole keyboard failed?  Probably not the keyboard.  Probably the encoder chip which is on the motherboard, the cable or something else.  Just a key or two?  Easier to repair than to find a whole other keyboard.  Key switches are available from people like Dr. Buggie on eBay.

 

What exactly is it doing or not doing?

 

 

 

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It’s almost impossible for a

It’s almost impossible for a whole IIe keyboard to fail. There’s no electronics on it, just a bunch of switched connecting different wires

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Wayne wrote:It’s almost
Wayne wrote:

It’s almost impossible for a whole IIe keyboard to fail. There’s no electronics on it, just a bunch of switched connecting different wires

 

Exactly...  if no keys at all are working then it is something else like the cable has come loose or broken or the encoder chip on the mobo has died.

 

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Considering the replies above

Considering the replies above, I looked up the schematic and listed the various ways the Apple IIe keyboard might stop working:

Here are the noteworthy ways the keyboard can be blocked on an Apple IIe:

  • Slot 1 can directly disable the keyboard by pulling-up ENKBD* on pin 35.  So it's worth removing any cards from slot 1 when troubleshooting keyboard issues.
  • 3600 PRO, the chip at position E14 may be faulty.  This chip scans the keyswitches and generates KSTRB and AKD signals.  (key-strobe and any-key-down)
  • 2716 ROM at position E12 may be faulty.  This chip generates the specific key codes for each key switch.
  • IOU input-output-unit chip at position E5 may be faulty.  This chip passes KSTRB and AKD to the CPU.
  • MMU memory-management-unit at position E4 could be disabling the keyboard ROM.  The MMU can block keyboard input via KBD* on pin 18.
  • Capacitors C70 or C71 might have failed shorted, which would cause the 3600 PRO to halt.
  • The keyboard might have been conspicuously physcially destroyed by a sledghammer, blowtorch, or quick-curing cement.  So the OP might already know this, but simply didn't mention it because it was obvious to him that the keyboard was beyond repair.

 

Whatever the cause, there's a simple safe way to test whether the motherboard's keyboard circuitry is working: with the power ON, go to the NUMERIC KEY PAD connector (J16) and connect the two end wires together and look to see if the computer starts typing repeated )))))) characters.  Connecting those two wires has exactly the same effect as attaching a numeric keypad and holding down the ")" key.

It should be safe to tinker with the NUMERIC KEY PAD connector because it doesn't have any vulnerable signals nor power connections.  Any pins on J16 can be safely connected to any other pins on the same connector without causing harm.  (That's exactly how a numeric key pad would work.)

 

If nothing else, this exercise led me to discover that the Apple IIe keyboard can be disabled by a card in slot 1, by pulling up pin 35.  I didn't know that until today.  In his book Understanding the Apple IIe, James Sather discusses the connection of ENKBD* at slot 1, acknowledging that there are no peripherals that make use of it.  He speculates, "The capability of disabling the keyboard ROM from Slot 1 is probably meant to support some motherboard production checkout test apparatus."

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