68kMLA Classic Interface
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| Mac IIfx Clock/Time not working | |
| Posted by: Johnnya101 on 2017-05-19 13:26:20 Title. Time does not advance, and stays still... Ive reset PRAM. Im confident the batteries are in correctly. Any ideas? | |
| Posted by: BadGoldEagle on 2017-05-19 13:34:00 Rotten traces? That can happen. Especially if you had leaky caps on that logic board... Get a MMU and check continuity. I bet one trace has gone bad. | |
| Posted by: ArmorAlley on 2017-05-19 13:41:37 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? | |
| Posted by: Johnnya101 on 2017-05-19 14:01:46 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 đ 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. | |
| Posted by: tjjq44 on 2020-02-02 10:35:46 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...   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? | |
Posted by: Bolle on 2020-02-02 10:55:42maybe Iï»ż'll have to replace the Nand gates and the related transistors?ï»żWorth a shot. I had a few IIci logicboards where those were dead. Replacing them fixed any weird startup/shutdown behavior. | |
| Posted by: tjjq44 on 2020-02-02 13:54:43 I can easily find the MMBT3906 and MMBT3904 but the PC74HC132T is quite expensive and I need two of them... Do anyone know a equivalent component? | |
| Posted by: Bolle on 2020-02-02 14:08:08 Any 74HC132 will do, they shouldnât cost more than 50 cents a piece. You donât need the exact same part from the same manufacturer thatâs 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) | |
| Posted by: tjjq44 on 2020-02-02 14:26:26 Ok thanks, I thought the pinout could be different... I'll try on aliexpress ;-) | |
| Posted by: toples50 on 2020-02-03 05:39:31 I have also shut down issue with my IIfx.I haven't  recap it yet unfortunately. | |
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