Mac Plus

Seek advice, give advice or tell others about your repair and restoration projects

Mac Plus

Postby Antz on Wed Jul 25, 2018 9:46 am

I just pulled out my old Mac Plus (been stored in its original box for the last 4 years), plugged it in and it started with flashing question mark disk. Put a system disk into the drive and away it went.

Mouse was working and keyboard all going OK.

Next step was to boot it up from the external SCSI drive (which I have had working away happily on another machine). So I shutdown the Plus and it has the dialog with the restart button, floppy disk ejects. I turn around to get the SCSI drive and here this big POP sound, turn back and there is some smoke coming out the back of my beloved Mac Plus :( but the screen is still displaying the dialog box.

Is that likely to be a capacitor that popped?
Posts: 16
Joined: Wed Jul 31, 2013 4:19 pm

Re: Mac Plus

Postby tezza on Wed Jul 25, 2018 11:06 am

A capacitor. Absolutely, most likely associated with the PSU.

There is good news though. (1) If the machine still works it's not something that's critical (and the event has not damaged anything critical) and (2) the damaged component should be easily visible.

Just replace it with one of the same type and capacitance, and problem fixed!
Tez (Terry Stewart) (Administrator)
Collection: ... /index.htm
Projects and Articles:
Twitter: @classiccomputNZ | YouTube: Terry Stewart
Trade Me: tezza5
Site Admin
Posts: 2380
Joined: Thu Jan 01, 1970 12:00 pm
Location: Palmerston North, New Zealand

Re: Mac Plus

Postby Antz on Wed Jul 25, 2018 12:44 pm

Looks like it should be fixable then

The main reason I turned it on was to make sure it worked and add it to the list of old Mac stuff that I am going to be clearing out. Would love to keep playing around with it all but don't really have the time and can do almost all the things i liked doing on the old machines with emulators now.

Hopefully will get it all sorted in next few weeks and list it here initially, just transferring all my old files and software onto newer machines. If anyone is round Upper Hutt and interested in looking at what I have to get rid of they are welcome to have a look before I list it all.

Can start with a Mac Plus (in original box) that needs at least one capacitor replaced :D
Posts: 16
Joined: Wed Jul 31, 2013 4:19 pm

Re: Mac Plus

Postby glc on Wed Jul 25, 2018 11:17 pm

It could be the RIFA (mains filter cap).
Sometimes they explode and other components suffer the consequences, or they let their smoke out.
If it has failed you should see a cracked plastic housing and some black area. They are typically yellow
It is a safety device for over voltage or spikes.
You can remove it for the sake of testing
Posts: 35
Joined: Tue Nov 25, 2014 5:00 am

Return to Repair and Restoration

Who is online

Users browsing this forum: No registered users and 8 guests