Hello All.
I recently picked up an Apple IIc (My first Apple II) that seems to mostly work except the disk activity LED on the keyboard is very dim. I thought originally it was dead but it is barely lighting so I replaced it and that was not the problem. The LED goes through nearby Resistor R1 which I removed and it does measure 178 ohms the same as R2 does for the power LED. This seems to go to PIN 11 of the keyboard connector, which is connected. I checked the tech reference manual for the schematics but I am not at all familiar with this awesome computer and I am learning as I go. I assume it makes its way to the drive but not sure what else to check. If I read the schematics right it goes to the GLU and the IWM ICs. It is getting some sort of signal/voltage but perhaps not enough.
Is there a way to turn on the drive activity light programmatically so as to test further? Edit: Yes there is via a BASIC line.
10 X=PEEK(-16151): X=PEEK(-16150)
That one live will turn on the drive motor.
I have traced the DISK ACTIVITY signal to pin 19 of the internal disk drive connector so there has to bee something in the drive itself that is causing the low voltage.
Any suggestions would be great and thank you.
I recently picked up an Apple IIc (My first Apple II) that seems to mostly work except the disk activity LED on the keyboard is very dim. I thought originally it was dead but it is barely lighting so I replaced it and that was not the problem. The LED goes through nearby Resistor R1 which I removed and it does measure 178 ohms the same as R2 does for the power LED. This seems to go to PIN 11 of the keyboard connector, which is connected. I checked the tech reference manual for the schematics but I am not at all familiar with this awesome computer and I am learning as I go. I assume it makes its way to the drive but not sure what else to check. If I read the schematics right it goes to the GLU and the IWM ICs. It is getting some sort of signal/voltage but perhaps not enough.
Is there a way to turn on the drive activity light programmatically so as to test further? Edit: Yes there is via a BASIC line.
10 X=PEEK(-16151): X=PEEK(-16150)
That one live will turn on the drive motor.
I have traced the DISK ACTIVITY signal to pin 19 of the internal disk drive connector so there has to bee something in the drive itself that is causing the low voltage.
Any suggestions would be great and thank you.
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