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Mac IIfx Clock/Time not working


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Do the batteries have enough of a charge to function properly? I've forgotten exactly how much of a charge it needs to work (3.2V maybe?). Someone here should know the figure. If you have a multimeter, you can check the voltage.

Are other settings forgotten, like AppleTalk settings, mouse-speed settings and the like? Can you boot cold-boot the IIfx from the power button on the keyboard?

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Brand new batteries.

 

Has not been recapped either, and its having the power off issues, so I think its safe to assume caps! Thats where the batteries are too, right by them :(

 

Luckily theres no visible leaking so it can't be too bad. Ill send it off and get it done soon once I get money.

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  • 2 years later...

Had exactely the same problem since I got my IIfx 5 years ago... The first thing I made when I got it was recapping but the problem was still there!

 

This WE I went on the problem to see if there was any broken trace with the power circuit and RTC schematics... but everything was fine...

 

iifx-start.jpg

iifx-rtc.jpg

In purple, the traces I tested were all OK!

 

At last resort I decided to pull a RTC chip from an old mac Classic in order to replace the IIfx's one... and... it works, clock is counting!!! What a surprise since I had never seen a RTC fail before!

 

I still have the power off issue (I have to unplug the mac for shutdown), maybe I'll have to replace the Nand gates and the related transistors?

Edited by tjjq44
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20 minutes ago, tjjq44 said:

maybe I'll have to replace the Nand gates and the related transistors?

Worth a shot. I had a few IIci logicboards where those were dead.

Replacing them fixed any weird startup/shutdown behavior.

Edited by Bolle
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Any 74HC132 will do, they shouldn’t cost more than 50 cents a piece.

You don’t need the exact same part from the same manufacturer that’s on there right now.

Any other type of 74*132 might work, but in circuits like this I would always use the same type (HC in this case)

Edited by Bolle
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