Macintosh Quadra 950 - Power Supply Issue

Looking on eBay, I found a rather clean Quadra 950 tower for sale with no bids at the moment.

It's has a 68040 33 Mhz processor, 40 MB RAM, though is lacking a HDD and 3.6v battery.

The seller says it was working fine until last July, though since then would be "randomly" shutting down after 30-60 minutes of use. Now he says it's only after a couple of minutes.

I would assume it's most likely the power supply and it needs new capacitors. However, my hardware diagnostic skills on old Macs is rather limited. I'm interested to know if anyone else has experienced using Quadra and whether something else could potentially be causing the issue.

Personally I thought it would make a nice project, considering it was top of the line back in the early 1990s.


  • Well, that kind of variable behavior does suggest a capacitor drying out, probably in the power supply. Not impossible it could be something else though. However, I have never really worked on Macs.

    My thought is that if it is good cosmetic condition, is something that interests you, and is a decent price, then you might want to go ahead and get it. Good condition stuff is getting harder to find. At worst you might wind up asking around on Mac forums for parts or hunting down a similar beat up unit for parts.

  • I would recommend hopping over to 68kMLA for Mac related stuff, particularly with hardware.

  • Thanks for the link - some interesting reading.

    I placed a bid, it's currently at a $1 and there's only a day left. A SCSI hard disk won't be so bad to find (not sure if anyone made SCSI adapters for SD cards and the like), though not sure about other Quadra parts. Anything pre-Power PC and it tends to be the Classics and SE/30s for sale. See what happens - I may not even get it.

    Here's a couple of photos to give you an idea:

  • That's a pretty clean machine. I say you'll get a great deal if you can resolve the issues.

    BTW Don't these things usually yellow? That's still platinum gray!

  • Nevermind, lost my chance while playing Fallout 4. Just one other bidder who at the last minute kept bidding up to a whole $36 to get it.

  • Too bad, they were the Cadillac of the 68000 based machines. 68040@50Mhz and you could get a couple hundred megabytes in there too. I ran A/UX 3.1 on mine when I had one. It was a sweet machine

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