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Mac Plus "happy mac" freeze during bootup

Posted by: CharlieFrown on 2016-11-01 08:27:33 Hi,  having problem with my Macintosh Plus, it never manages to boot operating system, instead it freezes after a while (like 5 seconds) of reading data. Doesnt matter if I try to boot it from floppy (100% bootable floppy inserted in working internal and external drives) or external hard disk with bootable System 6 (tried with other Mac) it's always the same, freezes with happy Mac icon (as seen on screen).  IWM, Bourns Filter? What should be tested first?

Posted by: CharlieFrown on 2016-11-01 13:04:19 ok not really freezing... as it stops booting from hard disk I can insert floppy and it's trying to read it, but no success.  Another thing is it correctly ejects non system floppy and I can manually eject any floppy with mouse button pressed, so I guess IWM chip is ok?

Posted by: CharlieFrown on 2016-11-02 15:08:19 Problem solved. Removed R8 resistor "256k bit memory" and used 4 x 1 MB memory chips (instead of 256 kB ones). Works smoothly!

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