Help me diagnose an Apple IIc Disk Drive issue

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Help me diagnose an Apple IIc Disk Drive issue

Hi, second time writing in the forum.

 

I have an issue with an Apple IIc that suddenly stopped communicating with the internal Disk Drive, no sound at all, no spin, no read/write. The computer boots and beeps and shows "Apple //c" and "Check Disk Drive" message. Got to add that the drive used to make sound, sping and read/write intermittently.

 

Proceeded to connect that same drive to an Apple IIe I happened to have and the drive makes sounds and spins, so the Disk Drive works. Then connected a known functioning drive from the Apple IIe to the Apple IIc and again no sound, no spin, I also discarded cable failure.

 

I suspect it is the IWM IC or the PAL20X4CNS from what I read online, any thoughts on how can I diagnose or try?

 

Thanks!!

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Does the internal IIc disk

Does the internal IIc disk drive work with no external drive connected?

 

If so perhaps you have a failing power supply.

 

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Definitely start by checking

Definitely start by checking that there is +12V at the floppy connector.

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jeffmazur wrote:Definitely
jeffmazur wrote:

Definitely start by checking that there is +12V at the floppy connector.

Is it the pin 1?

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I only have the internal disk

I only have the internal disk drive.

Coul you give me the values the PSU should output?

 

Thanks!

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 migueldelag wrote:jeffmazur

 

migueldelag wrote:
jeffmazur wrote:

Definitely start by checking that there is +12V at the floppy connector.

Is it the pin 1?

No. Pins 13,15,and 17.

 

The PSU puts out +12, -12. and +5VDC.

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migueldelag wrote:I only have
migueldelag wrote:

I only have the internal disk drive.

 

  Have you tried connecting an external drive to the IIc with no internal drive present?  Perhaps a smartport device like a Floppy Emu or Unidisk 3.5?

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