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#1 2016-11-01 18:36:48

Registered: 2016-11-01
Posts: 1

Macintosh Plus stuck during bootup


having problem with my Macintosh Plus, it never manages to boot operating system properly,  it "freezes" after a while (like 5 seconds) of reading data instead. 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 partition (tried successfully 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?

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?

Weird thing is Happy Mac icon is shown on a black background with just a grey boarder...

Last edited by charliefrown (2016-11-01 20:07:48)


#2 2016-11-06 19:06:32

From: North S.F. Bay Area, CA
Registered: 2014-05-23
Posts: 590

Re: Macintosh Plus stuck during bootup

Check your RAM. Also, depending on how much RAM you have, check to see that the little resistor near the RAM slots is present and soldered at both ends for 1MB, or unsoldered for 2.5MB or more.


Main Macs: Early '09 Mac Pro, Mid '12 MacBook Pro 13"
Secondary Macs: Early '08 Mac Pro, Mid '12 MacBook Pro 15"
Playthings: Mac SE/30, 3.0 GHz Mavericks-based HackServe, Many others....
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#3 2016-11-08 12:23:34

From: Sf, Mi
Registered: 2014-05-15
Posts: 956

Re: Macintosh Plus stuck during bootup

to go along with what CC said check your 5v rail.... should be right around 4.95 to 5.05... if its out of spec adjust the 5v cutoff adjustment on the AB...  But i am thinking ram too... pop ram out.... Spray ram simm slots with 91% IPA scrub with tooth brush...  spray with IPA again....  spray tooth brush,  so its clean... then spray slots and tooth brush again... hold MB over trash can so nasty saturated IPA has a place to drain... then clean ram simms same way... then let dry should only take about 5-10 minutes to fully dry... then pop Simms back in, take care with PLASTIC simm retention clips... they will snap off if you are careless.

#I Re-Cap √Mac √NeTX √Amiga Boards - A/B - PSU# (  Modern SCSI HD's - For Old Macs - Pre Cfg'd - 10k RPM! 73gb!! $50 + free shipping  -- Mac 128K Re-Ram kits (16 Chips) $35 + shipping, Floppy Issues?-> Bourns Filter Solution 128k - SE/30, $16 + shipping


#4 2016-11-17 20:31:41

Registered: 2016-11-15
Posts: 3

Re: Macintosh Plus stuck during bootup

Hi, my Plus is one of the early ones and those had SCSI problems with the external harddrive. Mine will work sometimes and sometimes not. Apple fixed it after a few weeks I think, with an updated ROM. Will it boot from floppy, when you disconnect the external harddrive?
I am using mine with floppys only.
- Poul


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