I just picked up a Macintosh IIx that was being sold as recapped and working, but when I got it home to turn it on, it showed no signs of life. Nothing out of the power supply, and pressing the power button on the back of the unit did absolutely nothing. After some research, it was found that the power supply could be turned on by applying three volts to Pin 15, and doing so worked. The machine turned on without a problem, and made the startup chime. I checked both PRAM batteries, and they seemed to be fine. I also tried applying three volts from my bench power supply to the battery holders, but pressing the power button still did nothing. However, the power button does work for turning off the machine once it has already been started. I was wondering what could be going wrong, and how the issue can be fixed.

Thanks!

⟐ Commented August 25, 2025 at 10:47 MST

1) PUSH START BUTTON ON KEYBOARD

2) SCREEN COMES ON

3) HAPPY FACE ICON COMES ON

4) WELCOME TO MACINTOSH LABEL COMES ON THEN GOES OFF

5) TOP OF SCREEN MENU COME ON AND STAYS.

( FILE-EDIT-VIEW-LABEL-SPECIAL)

6) HARD DISK ICON COMES ON WITH LABEL "HARD DISK"

7) TRASH ICON COMES ON , NO LABEL.

8) CLOCK COMES ON REPLACING CURSOR ARROW

9) CAN MOVE CURSOR (CLOCK ICON) WITH MOUSE

10 ) NOTHING ELSE WILL COME ON DESK TOP OR WILL WORK

11) REPLACED BOTH BATTERIES

12) ZAPPED PARAMETERS

13) ALL MY PEOPLE LIKE THIS COMPUTOR FOR OUR CAD CAM

WORK BETTER THAN OUR OTHER THREE SYSTEMS.

14) SUGGESTIONS ?

⟐ Commented July 19, 2022 at 11:52 MST